CN108328595B

CN108328595B - Carbon aerogel, preparation method thereof and pressure sensor

Info

Publication number: CN108328595B
Application number: CN201710302048.1A
Authority: CN
Inventors: 肖卓建; 周维亚; 王艳春; 解思深
Original assignee: Institute of Physics of CAS
Current assignee: Institute of Physics of CAS
Priority date: 2017-01-20
Filing date: 2017-05-02
Publication date: 2020-08-25
Anticipated expiration: 2037-05-02
Also published as: CN108328595A

Abstract

The invention provides carbon aerogel, a preparation method thereof and a pressure sensor, and belongs to the field of nano material research. The carbon aerogel which is composed of amorphous carbon and graphene through a mud brick structure and has omnidirectional compressibility and superelasticity and a preparation method thereof comprise the following steps: dispersing a saccharide additive and graphene oxide into a solvent to form a graphene oxide and additive mixed dispersion solution; drying the mixed solution to obtain graphene oxide aerogel containing an additive; the method comprises the following steps of carrying out high-temperature heat treatment on graphene oxide aerogel containing an additive under the protection of inert gas to obtain carbon aerogel, wherein the obtained carbon aerogel has omnidirectional compressible superelasticity, omnidirectional recoverable compressibility, high strength and high conductivity.

Description

Carbon aerogel, preparation method thereof and pressure sensor

Technical Field

The invention relates to the technical field of nano materials, in particular to carbon aerogel, a preparation method thereof and a pressure sensor.

Background

The aerogel has large specific surface area and high porosityThe most common aerogel is silicon dioxide aerogel which is widely applied to the fields of heat insulation, sound insulation, shock absorption and the like, in recent years, carbon aerogel, particularly graphene aerogel obtains wide attention of scientific researchers and industries, and graphene has high electrical conductivity (1 × 10)⁶S/m), high modulus (1TPa), high strength (130GPa) and high specific surface area (2630 m)²The novel two-dimensional material with excellent performances such as/g), the aerogel formed by taking graphene as a main body can endow the aerogel with new excellent characteristics, such as high strength, compression resistance, high conductivity and the like.

Chemical vapor deposition and redox methods are the main methods for realizing large-scale preparation of graphene, and two main methods for preparing graphene aerogel are developed on the basis of the two methods: template vapor deposition and solution self-assembly. The method comprises the steps of firstly carrying out chemical vapor deposition on three-dimensional porous materials such as foam nickel or silicon dioxide sponge and the like to obtain a continuous tubular graphene three-dimensional network by a template vapor deposition method, then etching a porous substrate, and then further drying and carrying out heat treatment to obtain the graphene aerogel. Although the graphene aerogel prepared by the method has high crystallinity and excellent electrical and mechanical properties, the microstructure of the graphene aerogel depends on the porous material of the substrate, the graphene aerogel is not easy to regulate and control, and the problem of high cost caused by the need of a complex process and extremely high temperature heat treatment (2250 ℃) is difficult to overcome. Compared with a template vapor deposition method, the solution self-assembly method does not need a deposition template, so the structure and the property of the solution self-assembly method are easy to regulate and control, and meanwhile, the method does not need a complex process and ultrahigh processing temperature, has low cost and is more suitable for industrialization. However, the mechanical and electrical properties of the carbon aerogel obtained by the existing solution self-assembly method are not good, and the carbon aerogel cannot be compared with the template vapor deposition method. Even if the graphene network is fixed by the composite carbon nanotubes or the macromolecules in the solution self-assembly method, the obtained aerogel does not have omnidirectional compressible superelasticity and omnidirectional recoverable compressibility, and simultaneously has low strength and conductivity. The omni-directionally compressible super-elasticity or omni-directionally recoverable compressibility is that the omni-directionally compressible super-elasticity or omni-directionally recoverable compressibility can recover more than 60% of the compressed length after the compression and the pressure are removed along any direction of a three-dimensional coordinate system (X-Y-Z).

In summary, there is no report on the preparation of carbon aerogel with omnidirectional compressible superelasticity, omnidirectional recoverable compressibility, high strength and high conductivity with low cost and good controllability.

The carbon aerogel with the advantages of omnidirectional compressibility, superelasticity, omnidirectional recoverable compressibility, high strength and high conductivity plays a decisive role in constructing novel compression-resistant flexible batteries, supercapacitors, sensors, brakes and other electronic devices, and is of great importance in developing carbon biological tissue scaffolds, ultralight mechanical damping porous materials and ultralight heat-insulating/sound-insulating porous materials based on the carbon aerogel in the future. Therefore, the development of the method for preparing the carbon aerogel with the omnidirectional compressible superelasticity, high strength and high conductivity has important scientific significance and application value, and has good controllability.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, develop a carbon aerogel with omnidirectional compressible superelasticity, omnidirectional recoverable compressibility, high strength and high conductivity, and provide a preparation method thereof.

Another object of the invention is: based on the carbon aerogel with omnidirectional compressible superelasticity, omnidirectional recoverable compressibility, high strength and high conductivity, the tactile and pressure sensor capable of omnidirectional detection of pressure, low detection limit and high sensitivity is provided.

In particular, the carbon aerogel provided by the invention is a composition, and is characterized in that: the carbon aerogel is formed by constructing graphene or partially reduced graphene oxide and amorphous carbon through a brick mud structure; the brick mud structure is a porous network-shaped composite structure which is similar to a brick mud structure and is formed by linking graphene or partially reduced graphene oxide and amorphous carbon, wherein the single-layer or multiple-layer graphene or partially reduced graphene oxide is used as a brick, and the amorphous carbon is used as a mud to coat or partially coat the graphene or partially reduced graphene oxide; the weight percentage of the components is as follows: 0.1-99.9% of graphene or partially reduced graphene oxide and 0.1-99.9% of amorphous carbon.

Preferably, the carbon aerogel has omni-directional compressible superelasticity and omni-directional recoverable compressibility.

Preferably, the carbon aerogel is macroscopically porous foam-like. The shape, size and dimension are not limited, and the density can be lower than 0.2mg/cm³. The pore size range is not limited, and may preferably be 1nm to 500. mu.m. Has excellent elasticity and recovery compressibility along different directions, namely omni-directional compressible super elasticity and omni-directional recovery compressibility. The compressive strength may be greater than 500kPa and the electrical conductivity may be greater than 80S/m.

Further, the carbon aerogel formed by graphene and amorphous carbon is composed of carbon element and does not contain other elements; the carbon aerogel formed by partially reduced graphene oxide and amorphous carbon, which consists of oxygen and carbon elements and contains no other elements;

wherein when the atomic percentage of oxygen element in the carbon aerogel is less than or equal to 1%, the carbon aerogel is full carbon aerogel.

Preferably, the atomic percent of oxygen element of the carbon aerogel is more than or equal to 0.01 percent, and the rest is carbon element.

Preferably, the atomic percent of oxygen element of the all-carbon aerogel is more than or equal to 0.01% and less than or equal to 1%, and the rest is carbon element.

Furthermore, the proportion of the constituent elements in the carbon aerogel can be adjusted at will.

Optionally, the atomic percentage of oxygen in the constituent elements of the carbon aerogel can be controlled to be 60% -50%, and the rest is carbon.

Optionally, the atomic percentage of oxygen in the constituent elements of the carbon aerogel can be controlled to be 50% -20%, and the rest is carbon.

Optionally, the atomic percentage of oxygen in the constituent elements of the carbon aerogel can be controlled to be 20% -10%, and the rest is carbon.

Optionally, the atomic percentage of oxygen in the constituent elements of the carbon aerogel can be controlled to be 10% -5%, and the rest is carbon. .

Optionally, the atomic percentage of oxygen in the constituent elements of the carbon aerogel can be controlled to be 5% -3%, and the rest is carbon.

Optionally, the atomic percentage of oxygen in the constituent elements of the carbon aerogel can be controlled to be 3% -1%, and the rest is carbon.

Optionally, the atomic percentage of oxygen in the constituent elements of the all-carbon aerogel can be controlled to be 0.1% -1%, and the rest is carbon.

Optionally, the atomic percentage of oxygen in the constituent elements of the all-carbon aerogel can be controlled to be 0% -0.6%, and the rest is carbon.

Optionally, the atomic percentage of oxygen in the constituent elements of the all-carbon aerogel can be controlled to be 0% -0.1%, and the rest is carbon.

Optionally, the atomic percentage of oxygen element in the constituent elements of the carbon aerogel can be controlled to be 0.1% -60%, and the rest is carbon element.

The carbon aerogel provided by the invention is ultra-light, and the density can be lower than 0.5mg/cm³。

The density of the carbon aerogel provided by the invention is adjustable within a certain range;

optionally, the carbon aerogel has a density in a range comprising less than 0.2mg/cm³。

Optionally, the carbon aerogel has a density in a range comprising 0.2 to 0.5mg/cm³。

Optionally, the carbon aerogel has a density range comprising greater than 0.2mg/cm³。

Optionally, the carbon aerogel has a density range comprising greater than 0.5mg/cm³。

Optionally, the carbon aerogel has a density in a range comprising 0.51-1mg/cm³。

Optionally, the carbon aerogel has a density in the range of 1-5mg/cm³。

Optionally, the carbon aerogel has a density in a range comprising 0.5 to 3mg/cm³。

Optionally, the carbon aerogel has a density in the range of 5-15mg/cm³。

Optionally, the carbon aerogel has a density in a range comprising 15-30mg/cm³。

Optionally, the carbon aerogel has a density in a range including 30-50mg/cm³。

Optionally, the carbon aerogel has a density in a range comprising 40-50mg/cm³。

Optionally, the carbon aerogel has a density in the range of 50-100mg/cm³。

Optionally, the density range of the carbon aerogel comprises 100-200mg/cm³。

Further, the pore size range of the carbon aerogel is adjustable within a certain range; preferably, it is tunable within 1 nm-500. mu.m.

Optionally, the pore size of the carbon aerogel ranges from 1nm to 100 nm.

Optionally, the pore size of the carbon aerogel ranges from 100nm to 10 μm.

Optionally, the pore size of the carbon aerogel ranges from 10 μm to 50 μm.

Optionally, the pore size of the carbon aerogel ranges from 50 μm to 200 μm.

Optionally, the pore size of the carbon aerogel ranges from 200 μm to 250 μm.

Optionally, the pore size range of the carbon aerogel comprises greater than 250 μm.

Further, the carbon aerogel has compressible super elasticity and recoverable compressibility;

in particular, the carbon aerogel has omni-directional compressible superelasticity and omni-directional recoverable compressibility;

wherein, the omni-directionally compressible superelasticity means that the aerogel can recover to the original length when the pressure is removed after being compressed along any direction; the omni-directional recoverable compressibility refers to the ability of the aerogel to recover more than 60% of its original length when compressed in any direction and then the pressure is removed.

Further, the strain of the omni-directionally compressible superelasticity and omni-directionally compressible recovery is tunable in the range of 0.1-99.9%.

Optionally, the strain range of the omni-directionally compressible superelasticity and omni-directionally compressible recovery comprises 0.1-20%.

Optionally, the strain range of the omni-directionally compressible superelasticity and omni-directionally compressible recovery comprises 20-40%.

Optionally, the strain range of the omni-directionally compressible superelasticity and omni-directionally compressible recovery comprises 40% -60%.

Optionally, the strain range of the omni-directionally compressible superelasticity and omni-directionally compressible recovery comprises 60-80%.

Optionally, the strain range of the omni-directionally compressible superelasticity and omni-directionally compressible recovery comprises 70-90%.

Optionally, the strain range of the omni-directionally compressible superelasticity and omni-directionally compressible recovery comprises 90-95.9%.

Optionally, the strain range of the omni-directionally compressible superelasticity and omni-directionally compressible recovery comprises 96-99.9%.

Optionally, the strain range of the omni-directionally compressible superelasticity and omni-directionally compressible recovery comprises 98.5-99.9%.

Further, the carbon aerogel has the characteristics of ultra-light weight and high strength. Can bear the compression of a plurality of weights reaching the self weight and maintain the structural integrity. The density, graphene to amorphous carbon ratio, and the time of heat treatment all control the ratio of sustainable (i.e., able to withstand compression while maintaining its structural integrity) weight to self weight of the aerogel.

Preferably, the ratio of the amount of heavy substances capable of being borne by the aerogel to the weight of the aerogel can reach more than 10 ten thousand.

Alternatively, the ratio of the amount of heavy materials that the aerogel can bear to the weight of the aerogel can be less than or equal to 1 ten thousand.

Optionally, the ratio of the amount of heavy material to the weight of the aerogel can range from 1 ten thousand to 5 ten thousand.

Optionally, the ratio of the amount of heavy material to the weight of the aerogel can be in the range of 5.1-10 ten thousand.

Optionally, the ratio of the amount of heavy material to the self weight of the aerogel can be in the range of 10-20 ten thousand.

Optionally, the ratio of the amount of heavy materials that the aerogel can bear to the weight of the aerogel can be in a range of more than 10 ten thousand.

Optionally, the ratio of the amount of heavy material to the weight of the aerogel can be in the range of 20-50 ten thousand.

Optionally, the ratio of the amount of heavy material to the weight of the aerogel can be in the range of 30-50 ten thousand.

Optionally, the ratio of the amount of heavy materials that the aerogel can bear to the weight of the aerogel can be in a range of more than 30 ten thousand.

Further, the carbon aerogel is macroscopically in the form of a porous foam of any geometric shape; the carbon aerogel can be machined or cut into any geometric shape.

Preferably, said carbon aerogel is a porous foam having macroscopically any geometric shape; can be machined or cut into any shape. Comprises a regular sphere, a cube, a cylinder and a polygonal cylinder; an irregular geometry; flakes, films of any shape; fibers and nanowires.

Preferably, the carbon aerogel is not limited in macroscopic size and can be as thin as 1 nanometer.

Preferably, the carbon aerogel is dimensionally unlimited, including three-dimensional, such as a block of any geometric shape; two-dimensional, such as nanoplatelets, films; one dimension, such as nanofiber, nanowire; zero-dimensional, such as nanospheres.

Furthermore, the brick mud structure is a porous network-shaped composite structure similar to a brick mud structure formed by connecting a single layer to several layers of graphene or partially reduced graphene oxide sheet layers serving as bricks and amorphous carbon generated by pyrolysis additives serving as mud; the weight percentage of the components is as follows: 0.1-99.9% of graphene or partially reduced graphene oxide and 0.1-99.9% of amorphous carbon.

Preferably, the graphene is 10% -90% and the amorphous carbon is 10% -80%.

Preferably, the graphene is 50% -80% and the amorphous carbon is 20% -50%.

The invention also provides a preparation method of the omnidirectional compressible super-elastic carbon aerogel, which comprises the following steps:

dispersing an additive and graphene oxide into a solvent to form a graphene oxide and additive mixed solution;

drying the mixed solution to obtain graphene oxide aerogel containing an additive;

and carrying out high-temperature heat treatment on the graphene oxide aerogel containing the additive under the protection of inert gas to obtain carbon aerogel or all-carbon aerogel.

Further, the additive is one or more of monosaccharide, disaccharide, oligosaccharide or polysaccharide;

preferably, the monosaccharide is one or more of glucose, fructose, galactose and ribose;

preferably, the disaccharide is one or more of maltose, sucrose and lactose;

preferably, the oligosaccharide is one or more of raffinose and stachyose;

preferably, the polysaccharide is one or more of starch, cellulose, glycogen and xylose.

Further, the solvent is a solvent for dispersing the additive and the graphene oxide, and water and an organic solvent are commonly used;

preferably, the solvent is one or a mixture of water, ethanol, acetone, dimethylformamide and carbon tetrachloride.

Further, the drying method for drying the mixed solution containing the additive and the graphene oxide is not limited;

preferably, the drying method for drying the mixed solution containing the additive and the graphene oxide is one or more of freeze drying, supercritical drying, vacuum drying and atmospheric pressure thermal drying.

Further, the temperature range of the high-temperature heat treatment is not limited, and the time of the high-temperature heat treatment is not limited;

preferably, the temperature range of the high-temperature heat treatment is 200-2500 ℃;

preferably, the time of the high-temperature heat treatment is 0.1-100 h.

Further, in the high-temperature heat treatment process, the higher heat treatment temperature and the longer heat treatment time are adopted, so that carbon aerogel with higher reduction degree and lower oxygen content, even all-carbon aerogel without oxygen can be obtained.

Optionally, the carbon aerogel comprises lightly reduced carbon aerogel having an atomic percent of elemental oxygen in the range of 10% to 60%.

Optionally, the carbon aerogel comprises moderately reduced carbon aerogel having an atomic percent of elemental oxygen in the range of 1% to 10%.

Optionally, the carbon aerogel (including all-carbon aerogel) comprises a highly reduced carbon aerogel (including all-carbon aerogel) having an atomic percent of elemental oxygen in an amount of 0.5% to 1%.

Optionally, the carbon aerogel (including all-carbon aerogel) comprises extremely highly reduced carbon aerogel (including all-carbon aerogel), and the atomic percentage of oxygen element is less than or equal to 0.5%.

Optionally, the carbon aerogels (including all-carbon aerogels) have a "brick mud" structure. The brick mud structure is a porous network composite structure similar to a brick mud structure, wherein a single layer to several layers of graphene sheet layers are used as bricks, and amorphous carbon generated by pyrolysis of an additive is used as mud for connection.

Further, the carbon aerogels (including all-carbon aerogels) have omni-directional compressible superelasticity, omni-directional recoverable compressibility, high strength, and high electrical conductivity.

Compared with the prior art, the invention has the following beneficial effects:

(1) compared with the template vapor deposition method, the method for preparing the carbon aerogel (including the all-carbon aerogel) does not need the step of chemical vapor deposition, so that complex chemical vapor deposition equipment is not needed, the preparation method is simple and convenient, and the cost is low. The template vapor deposition method utilizes porous metal as a substrate to deposit graphene, so that the microstructure of the graphene depends on the structure of the porous metal and is a network formed by tubular graphene; the brick mud structure carbon aerogel prepared by the invention is a composite structure network consisting of lamellar graphene and amorphous carbon, and can also be obtained in some cases; both the microstructure and the composition of the two are very different.

(2) Compared with the existing solution self-assembly method, the 'brick mud' structure carbon aerogel (including all-carbon aerogel) prepared by the invention is composed of amorphous carbon generated by pyrolysis of graphene and saccharides, and is different from the aerogel prepared by the existing solution self-assembly method in composition components (namely, the aerogel prepared by the existing solution self-assembly method is composed of high molecules and graphene, graphene and carbon nano tubes or only graphene). In the brick mud structure, due to a synergistic effect generated by strong pi-pi interaction between amorphous carbon and graphene, the prepared carbon aerogel porous network is firmer, has omnidirectional compressible superelasticity and omnidirectional recoverable compressibility, and has strength and conductivity far higher than those of the aerogel prepared by the existing solution self-assembly method.

(3) Compared with the method for pyrolyzing the mixture of chitosan and graphene oxide (Nature Communications, 2016,7 and 12920), the carbon aerogel prepared by the method disclosed by the invention has the elements of carbon and partial oxygen, and the aerogel prepared by the method for pyrolyzing the mixture of chitosan and graphene oxide has the composition containing 6% of nitrogen as well as carbon and oxygen, so that the components of the carbon aerogel and the oxygen are greatly different. The additive used for preparing the aerogel is micromolecular saccharide, and the macromolecular chitosan adopted by the method for pyrolyzing the mixture of the chitosan and the graphene oxide is different in essence. The preparation process of the invention does not need to use liquid nitrogen to treat the mixed liquid. The carbon aerogel network prepared by the method is firmer, has omnidirectional superelasticity and omnidirectional recoverable compressibility, and has strength and conductivity far greater than those of the aerogel prepared by the method.

(4) The carbon aerogel (including all-carbon aerogel) with the graphene and amorphous carbon composite network structure in the 'clay brick structure' has omni-directional compressible superelasticity, omni-directional recoverable compressibility, high strength and high conductivity, and can be used for constructing novel compression-resistant electronic devices such as flexible batteries, supercapacitors, sensors, brakes and the like. Can also be used as a carbon biological tissue scaffold, an ultralight mechanical damping porous material and an ultralight heat/sound insulation porous material.

The invention provides a pressure sensor which can be used for detecting the pressure of carbon aerogel in any direction; the structure is as follows: the carbon aerogel, the electrode and the electric signal measuring device for measuring the resistance value between the electrode and the carbon aerogel. Conductive silver paste is arranged between the aerogel and the electrode and is used for eliminating the influence of contact resistance on signals.

The pressure sensor adopts the bulk resistance effect as the sensing mechanism, has the advantages of large detection force range, higher sensitivity, low energy consumption and good stability, and can detect the pressure in any direction.

The invention also provides a touch and pressure sensor which can be used for detecting the touch and pressure of the carbon aerogel in any direction; the structure is as follows: the carbon aerogel, the electrode in surface contact with the carbon aerogel, and the electrical signal measuring device for measuring the electrical resistance between the electrode and the carbon aerogel, as described above.

The touch and pressure sensor provided by the invention is a sensor which can detect pressure omnidirectionally, has low detection lower limit and high sensitivity based on the carbon aerogel.

According to the touch and pressure sensor provided by the invention, an interface contact resistance effect rather than a bulk piezoresistive effect is adopted as a sensing mechanism, the lower limit of the detection force can reach less than or equal to 15Pa (about 10Pa corresponds to light touch on human touch), and the sensitivity is adjustable; preferably, the energy consumption can be adjusted as high as 10/kPa; preferably, it may be lower than 30 μ W.

Optionally, the contact interface between the electrode and the carbon sponge is free of any adhesive or mechanical attachment fixation.

Further, the electric signal of the output of the sensor is not limited. In specific embodiments, the electrical signal output by the sensor may be current, voltage, resistance.

Further, the detection lower limit and the working range of the aerogel pressure sensor are controlled by adopting different aerogels as working materials.

Optionally, the sensor includes a tactile sensor having a detection lower limit of 15Pa or less for a small pressure.

Optionally, the sensor comprises a tactile sensor having a lower detection limit of 50Pa or less for moderate pressure.

Optionally, the sensor may further comprise a pressure sensor with a working range of 15Pa to 200Pa for a smaller pressure.

Optionally, the sensor comprises a pressure sensor operating in the range of 200Pa-10kPa for moderate pressures. A pressure sensor operating in the range of 100Pa-5kPa for medium pressures may also be included.

Optionally, the sensor comprises a pressure sensor operating over a range of greater than 10kPa for high pressures.

Optionally, the sensor comprises a pressure sensor operating over a range of greater than 100kPa for high pressures.

Preferably, the tactile and pressure sensor employs conductive carbon materials as electrodes and leads, and the resulting sensor is an all-carbon tactile and pressure sensor.

Further, the all-carbon tactile and pressure sensor is ultra-light in weight.

Further, the all-carbon touch and pressure sensor can operate in extremely harsh environments. The working temperature range is wide, and the device can normally work at extremely low temperature; is resistant to corrosion by acid, alkali and salt.

the touch and pressure sensor based on the omnidirectional compressible super-elasticity, high-strength and high-conductivity carbon aerogel and capable of detecting the pressure in any direction not only enlarges the working range of the sensor and improves the working capacity, but also reduces the arrangement cost of the sensor. The lower detection limit is low, the sensitivity is high, and the sensor is suitable for monitoring human health signals and being used as a touch sensor of mechanical bionic hands. In particular, when a conductive carbon material such as carbon nanotube or graphene is used as an electrode and a wire, an all-carbon sensor can be prepared. The all-carbon sensor has the characteristics of light weight, wide working temperature range, acid and alkali resistance and salt corrosion resistance, and has wide application prospects in special occasions requiring touch and pressure detection, such as aerospace, strong corrosion environments and the like.

The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings.

Drawings

Some specific embodiments of the invention will be described in detail hereinafter, by way of illustration and not limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

FIG. 1 is a microscopic image of a carbon aerogel according to an embodiment of the present invention;

FIG. 2 is a stress-strain curve for compression of a carbon aerogel in accordance with an embodiment of the present invention;

FIG. 3 is a stress-strain curve of a carbon aerogel according to an embodiment of the present invention when compressed in an axial direction;

FIG. 4 is a stress-strain curve of a carbon aerogel according to an embodiment of the present invention when compressed in another axial direction;

FIG. 5 is a stress-strain curve of a carbon aerogel according to an embodiment of the present invention when compressed in another axial direction;

FIG. 6 is a schematic cross-sectional view of a tactile and pressure sensor capable of detecting tactile sensation and pressure in any direction according to embodiment 13 of the present invention;

FIG. 7 is a schematic cross-sectional view of a tactile and pressure sensor capable of detecting tactile sensation and pressure in any direction according to embodiment 14 of the present invention;

FIG. 8 is a schematic cross-sectional view of a tactile and pressure sensor capable of detecting tactile sensations and pressure in eight different directions according to example 15 of the present invention;

FIG. 9 is a schematic cross-sectional view of a tactile and pressure sensor capable of detecting tactile sensation and pressure in six different directions according to embodiment 16 of the present invention;

FIG. 10 is a schematic cross-sectional view of a tactile and pressure sensor capable of detecting tactile sensations and pressure in eight different directions according to example 17 of the present invention;

FIG. 11 is a schematic cross-sectional view of a tactile and pressure sensor capable of detecting tactile sensations and pressure in six different directions according to example 18 of the present invention;

FIG. 12 is a schematic diagram of a tactile and pressure sensor capable of detecting tactile and pressure in two different directions according to example 19 of the present invention;

FIG. 13 is a process for preparing a carbon aerogel in accordance with the present invention.

The notation in the figure is:

reference numbers in the figures: 1. an electrode located in the center of the aerogel; 2. an electrical signal measuring device; 3. an electrode which can freely move along any direction; 4. spherical aerogel; 5. a direction vector of an arbitrary direction; 6. projection of the direction vector in the XOY plane; 7. the included angle between the direction vector and the Z axis; 8. the projection of the direction vector in the XOY plane forms an included angle with the positive direction of the X axis; 9. a cylindrical aerogel; 10. the electrodes are uniformly distributed in eight different directions of the cylindrical surface of the aerogel; 11. interdigital electrodes 3 on the surface of the aerogel and the thin-film aerogel.

Detailed Description

The present invention is described in detail by way of embodiments, which are only used for further illustration of the present invention and are not to be construed as limiting the scope of the present invention, and other people who have made some non-essential changes and modifications according to the above disclosure belong to the scope of the present invention.

The carbon aerogel, the preparation method thereof and the pressure sensor are formed by constructing graphene or partially reduced graphene oxide and amorphous carbon through a brick mud structure; the brick mud structure is a porous network-shaped composite structure which is similar to a brick mud structure and is formed by linking a plurality of layers of graphene or partially reduced graphene oxide serving as bricks and amorphous carbon serving as mud to coat or partially coat the graphene or the partially reduced graphene oxide so as to enable the graphene or the partially reduced graphene oxide and the amorphous carbon to be connected; the weight percentage of the components is as follows: 0.1-99.9% of graphene or partially reduced graphene oxide and 0.1-99.9% of amorphous carbon, wherein the composition of the graphene or partially reduced graphene oxide is one or the combination of two of oxygen and carbon elements; in the combination, when the atomic percent of oxygen element of the carbon aerogel is less than or equal to 1%, the carbon aerogel can be called as all-carbon aerogel.

As shown in fig. 1, the carbon aerogel is macroscopically in the form of a porous foam of arbitrary geometry. Can be machined or cut into any geometric shape; shape, size, and dimensions are not limited; the density can be lower than 0.2mg/cm³(ii) a The pore size range is not limited, and the pore size range is preferably 1nm-500 μm; the compressive strength may be greater than 500 kPa; as shown in fig. 2-5, the carbon aerogel has omni-directional compressible superelasticity, omni-directional recoverable compressibility, and electrical conductivity; wherein, the omni-directionally compressible superelasticity means that the carbon aerogel can be restored to the original length when the pressure is removed after being compressed along any direction; the omni-directional recoverable compressibility refers to the ability of the carbon aerogel to recover more than 60% of its original length when compressed in any direction and then the pressure is removed.

As shown in fig. 13, the preparation method of the omnidirectionally compressible superelastic carbon aerogel comprises the following steps: 1) dispersing an additive and graphene oxide into a solvent to form a graphene oxide and additive mixed solution; 2) drying the mixed solution to obtain graphene oxide aerogel containing an additive; 3) and carrying out high-temperature heat treatment on the graphene oxide aerogel containing the additive under the protection of inert gas to obtain carbon aerogel or all-carbon aerogel.

Wherein the additive is one or more of monosaccharide, disaccharide, oligosaccharide or polysaccharide;

preferably, the disaccharide is one or more of maltose, sucrose and lactose;

preferably, the oligosaccharide is one or more of raffinose and stachyose;

Wherein the solvent is water and an organic solvent for dispersing the additive and the graphene oxide;

Wherein the drying method for drying the mixed solution containing the additive and the graphene oxide is one or more of freeze drying, supercritical drying, vacuum drying and normal-pressure heat drying.

The temperature range of the high-temperature heat treatment is not limited, and the time of the high-temperature heat treatment is not limited;

preferably, the time of the high-temperature heat treatment is 0.1-100 h.

In the preparation process, the additive is coated or partially coated on the surface of the graphene oxide sheet layer and is attached to a gap between the graphene oxide sheet layer and the sheet layer, and after heat treatment, the graphene oxide is reduced into graphene or partially reduced graphene oxide; the additive is pyrolyzed and carbonized to generate amorphous carbon, coats or partially coats the surface of a reduced or partially reduced graphene oxide sheet layer (often also referred to as a graphene sheet layer) and is filled or partially filled in a gap between the reduced or partially reduced graphene oxide sheet layer and the sheet layer, so that a stronger connecting or welding effect is achieved; forming a brick mud structure. After the temperature is reduced, the structure of the brick mud is maintained, and the carbon aerogel (including all-carbon aerogel) with omnidirectional compressibility and superelasticity is obtained; the brick mud structure carbon aerogel (including all-carbon aerogel) disclosed by the invention not only has omnidirectional compressible superelasticity and omnidirectional compressible recoverability, but also has strength and conductivity far greater than those of other carbon aerogels prepared from graphene oxide.

The pressure sensor adopts the bulk resistance effect as the sensing mechanism, has large and adjustable detection force range, higher and adjustable sensitivity, low energy consumption and good stability, and can detect the pressure in any direction. The invention also provides a touch and pressure sensor which can be used for detecting the touch and pressure of the carbon aerogel in any direction; the structure is as follows: the carbon aerogel, the electrode in surface contact with the carbon aerogel, and the electrical signal measuring device for measuring the electrical resistance between the electrode and the carbon aerogel, as described above.

The touch and pressure sensor adopts an interface contact resistance effect rather than a bulk piezoresistive effect as a sensing mechanism, the lower limit of detection force can reach less than or equal to 15Pa (about 10Pa corresponds to light touch on human touch), the sensitivity can be adjusted, preferably 100/kPa can be reached, the energy consumption can be adjusted, and preferably 30 muW can be lower.

Optionally, the sensor comprises a pressure sensor with a working range of 15Pa to 200Pa for a smaller pressure.

Optionally, the sensor comprises a pressure sensor operating in the range of 200Pa-10kPa for moderate pressures.

Optionally, the sensor may further comprise a pressure sensor operating in the range of 100Pa-5kPa for medium pressures.

Preferably, the tactile and pressure sensor uses conductive carbon material as electrodes and leads, and the obtained sensor is an all-carbon tactile and pressure sensor, wherein the electrodes are conductive materials which do not react with carbon aerogel. Preferably, a rigid electrode made of a metal such as gold, silver, copper, or a composite thereof; the electrode comprises carbon nanotubes, graphene, metal nanowires, transparent conductive oxide loaded on a flexible substrate, conductive polymers and a compound of the transparent conductive oxide and the conductive polymers, and the number and the positions of the electrodes are not limited.

Further, all-carbon tactile and pressure sensors are ultra-light in weight.

Furthermore, the all-carbon touch and pressure sensor can work in extremely severe environment, has wide working temperature range, can normally work at extremely low temperature, and resists corrosion of acid, alkali and salt.

The touch and pressure sensor based on the omnidirectional compressible super-elasticity, high-strength and high-conductivity carbon aerogel and capable of detecting the pressure in any direction not only enlarges the working range of the sensor and improves the working capacity, but also reduces the arrangement cost of the sensor, has low detection lower limit and high sensitivity, and is suitable for being used as a touch sensor for monitoring human health signals and mechanically simulating hands. In particular, when a conductive carbon material such as carbon nanotube or graphene is used as an electrode and a wire, an all-carbon sensor can be prepared. The all-carbon sensor has the characteristics of light weight, wide working temperature range, acid and alkali resistance and salt corrosion resistance, and has wide application prospects in special occasions requiring touch and pressure detection, such as aerospace, strong corrosion environments and the like.

Specific example 1:

step (a) 10 parts by mass of graphene oxide and 40 parts by mass of sucrose are dispersed in 500 parts by mass of water to form a graphene oxide and additive dispersion liquid.

And (b) injecting the graphene oxide and sucrose dispersion liquid into a hollow spherical mold for freeze drying to obtain the hollow spherical graphene oxide aerogel containing the additive.

And (c) carrying out heat treatment on the hollow spherical graphene oxide aerogel containing the additive for 4h at the temperature of 600 ℃ under the protection of nitrogen atmosphere to obtain the hollow spherical carbon aerogel.

The hollow spherical carbon aerogel graphene obtained by the method accounts for 80% and the amorphous carbon accounts for 20%. The oxygen element accounts for 20 atomic percent and is slightly reduced carbon aerogel. All have omni-directional compressible super-elasticity, and the recoverable compression strain along different directions is 80-99%. The strength is greater than 700 kPa. The density is 10mg/cm³The conductivity is more than 100S/m. The ratio of the amount of the heavy substances to the weight of the heavy substances is 1 ten thousand. Compared with graphene aerogel of composite carbon nano tubes, PDMS and PPY, the carbon aerogel prepared by the method has omnidirectional compressibility and superelasticity, and is more excellent in strength and conductivity.

In other embodiments provided by the present invention, the additive is one or more of monosaccharide, disaccharide, oligosaccharide or polysaccharide; the proportion of the additive and the graphene oxide is adjustable at will; the dispersant can be water and an organic solvent; the heat treatment temperature can be changed within the range of 200 ℃ and 2500 ℃; the graphene proportion of the obtained carbon aerogel is adjustable within the range of 10% -90%; the proportion of oxygen element is adjustable within 0.1-60%, and the rest elements are carbon elements and do not contain other elements; the recoverable strain is adjustable within 0.1-99.9%; the density can be adjusted in a large range, and preferably can be more than 10mg/cm³。

Specific example 2:

step (a) disperses 5 parts by mass of graphene oxide into 500 parts by mass of water to form a graphene oxide and additive dispersion liquid.

And (b) injecting the graphene oxide dispersion liquid into a cuboid-shaped mold for supercritical drying to obtain cuboid-shaped graphene oxide aerogel, wherein the additive accounts for 0%, and the graphene oxide accounts for 100%.

And (c) carrying out heat treatment on the cuboid graphene oxide aerogel for 4 hours at 700 ℃ under the protection of nitrogen atmosphere to obtain the cuboid carbon aerogel.

The carbon aerogel graphene obtained by the method accounts for 100% and does not contain amorphous carbon. The oxygen element accounts for 30 atomic percent and is slightly reduced carbon aerogel. The composite material does not have omnidirectional compressible superelasticity, the recoverable strain is 0%, and the composite material has recoverable compressibility and can recover 50% of the original length when the pressure is removed after compression. The density is 0.2mg/cm³. The conductance is less than 80S/m.

In other embodiments provided by the present invention, the additive is one or more of monosaccharide, disaccharide, oligosaccharide or polysaccharide; the proportion of the additive and the graphene oxide is adjustable at will; the dispersant can be water and an organic solvent; the heat treatment temperature can be changed within the range of 200 ℃ and 2500 ℃; the graphene proportion of the obtained carbon aerogel is adjustable within the range of 10% -90%; the proportion of oxygen element is adjustable within 0.1-60%, and the rest elements are carbon elements and do not contain other elements; the recoverable strain is adjustable within 0.1-99.9%; the density is adjustable in a large range, and preferably can be less than or equal to 0.5mg/cm³。

Specific example 3

Dispersing 5 parts by mass of glucose into 500 parts by mass of ethanol to form graphene oxide and an additive dispersion liquid.

And (b) injecting the glucose dispersion liquid into a sphere to perform supercritical drying, wherein the obtained spherical glucose aerogel additive accounts for 100%, and the graphene oxide accounts for 0%.

And (c) carrying out heat treatment on the spherical glucose aerogel for 0.5h at 800 ℃ under the protection of nitrogen atmosphere to obtain spherical carbon aerogel.

The spherical aerogel obtained by the method contains 100% of amorphous carbon and does not contain graphene. The oxygen element accounts for 40 atomic percent and is slightly reduced carbon aerogel. The uneven structure has omnidirectional compressible superelasticity, the recoverable strain is 0%, the recoverable compressibility is realized, and 50% of the original length can be recovered when the pressure is removed after compression. The density is 50mg/cm³. The conductivity is less than 100S/m.

In other embodiments provided by the present invention, the additive is one or more of monosaccharide, disaccharide, oligosaccharide or polysaccharide; the proportion of the additive and the graphene oxide is adjustable at will; the dispersant can be water and an organic solvent; the heat treatment temperature can be changed within the range of 200 ℃ and 2500 ℃; the graphene proportion of the obtained carbon aerogel is adjustable within the range of 10% -90%; the proportion of oxygen element is adjustable within 0.1-60%, and the rest elements are carbon elements and do not contain other elements; the recoverable strain is adjustable within 0.1-99.9%; the density is adjustable in a wide range, preferably 0.2mg/cm³-200mg/cm³The range is adjustable.

Specific example 4:

step (a)5 parts by mass of graphene oxide and 1 part by mass of glucose are dispersed in 500 parts by mass of dimethylformamide to form a graphene oxide and additive dispersion liquid.

And (b) injecting the graphene oxide and glucose dispersion liquid into a film-shaped mold for freeze drying to obtain the spherical shell-shaped graphene oxide aerogel containing the additive.

And (c) carrying out heat treatment on the thin-film graphene oxide aerogel containing the additive for 2h at 900 ℃ under the protection of nitrogen atmosphere to obtain the thin-film carbon aerogel.

The film-shaped carbon aerogel graphene prepared by the method accounts for 50% and the amorphous carbon accounts for 50%. The oxygen element accounts for 9 atomic percent and is the moderate reduced carbon aerogel. All have omni-directional compressible super-elasticity, and the recoverable compression strain along different directions is 70-89%. The strength is greater than 700 kPa. The density is 15mg/cm³The conductivity is more than 100S/m. The ratio of the amount of the heavy substances to the weight of the heavy substances is 3 ten thousand. And composite carbon nanoCompared with graphene aerogel of a rice pipe, PDMS and PPY, the carbon aerogel prepared by the method has omnidirectional compressibility and superelasticity, and is more excellent in strength and conductivity.

Specific example 5:

step (a)5 parts by mass of graphene oxide and 5 parts by mass of lactose are dispersed in 500 parts by mass of water to form a graphene oxide and additive dispersion liquid.

And (b) injecting the graphene oxide and lactose dispersion liquid into a spherical mould for freeze drying to obtain the cubic graphene oxide aerogel containing the additive.

And (c) carrying out heat treatment on the spherical graphene oxide aerogel containing the additive for 5 hours at 1000 ℃ under the protection of nitrogen atmosphere to obtain the spherical carbon aerogel.

The spherical carbon aerogel graphene obtained by the method accounts for 20% and the amorphous carbon accounts for 80%. The oxygen element accounts for 3 atomic percent and is the moderate reduced carbon aerogel. All have omni-directional compressible super-elasticity, and the recoverable compression strain along different directions is 60-89%. The strength is greater than 700 kPa. The density was 9mg/cm³The conductivity is more than 100S/m. The ratio of the weight of the heavy material to the self weight is 10 ten thousand. Compared with graphene aerogel of composite carbon nano tubes, PDMS and PPY, the carbon aerogel prepared by the method has omnidirectional compressibility and superelasticity, and is more excellent in strength and conductivity.

In other embodiments of the invention, the additive is a monosaccharide, disaccharide, oligosaccharide orOne or more of polysaccharides; the proportion of the additive and the graphene oxide is adjustable at will; the dispersant can be water and an organic solvent; the heat treatment temperature can be changed within the range of 200 ℃ and 2500 ℃; the graphene proportion of the obtained carbon aerogel is adjustable within the range of 10% -90%; the proportion of oxygen element is adjustable within 0.1-60%, and the rest elements are carbon elements and do not contain other elements; the recoverable strain is adjustable within 0.1-99.9%; the density is adjustable in a wide range, preferably 0.2mg/cm³-200mg/cm³The range is adjustable.

Specific example 6:

step (a)5 parts by mass of graphene oxide and 10 parts by mass of sucrose are dispersed in 500 parts by mass of water to form a graphene oxide and additive dispersion liquid.

And (b) injecting the graphene oxide and sucrose dispersion liquid into a cylindrical mold for freeze drying to obtain cylindrical graphene oxide aerogel containing the additive.

And (c) carrying out heat treatment on the graphene oxide aerogel containing the cylindrical additive for 14h at 900 ℃ under the protection of a nitrogen atmosphere to obtain the cylindrical carbon aerogel.

The cylindrical carbon aerogel graphene obtained by the method accounts for 20% and the amorphous carbon accounts for 80%. The oxygen element accounts for 10 atomic percent and is the moderate reduced carbon aerogel. All have omni-directional compressible super-elasticity, and the recoverable compression strain along different directions is 60-89%. The strength is greater than 700 kPa. The density is 4mg/cm³The conductivity is more than 100S/m. The ratio of the amount of the heavy substances to the weight of the heavy substances is 20 ten thousand. Compared with graphene aerogel of composite carbon nano tubes, PDMS and PPY, the carbon aerogel prepared by the method has omnidirectional compressibility and superelasticity, and is more excellent in strength and conductivity.

In other embodiments provided by the present invention, the additive is one or more of monosaccharide, disaccharide, oligosaccharide or polysaccharide; the proportion of the additive and the graphene oxide is adjustable at will; the dispersant can be water and an organic solvent; the heat treatment temperature can be changed within the range of 200 ℃ and 2500 ℃; the graphene proportion of the obtained carbon aerogel is adjustable within the range of 10% -90%; the proportion of oxygen element is 0.1-6 percentThe content of the carbon is adjustable within 0 percent, and the rest elements are carbon elements and do not contain other elements; the recoverable strain is adjustable within 0.1-99.9%; the density is adjustable in a wide range, preferably 0.2mg/cm³-200mg/cm³The range is adjustable.

Specific example 7:

step (a)5 parts by mass of graphene oxide and 50 parts by mass of starch are dispersed in 500 parts by mass of water to form a graphene oxide and additive dispersion liquid.

And (b) injecting the graphene oxide and starch dispersion liquid into an I-shaped mold for freeze drying to obtain the graphene oxide aerogel containing the additive in the shape of a flower pot.

And (c) carrying out heat treatment on the I-shaped graphene oxide aerogel containing the additive for 40h at 1200 ℃ under the protection of nitrogen atmosphere to obtain the I-shaped carbon aerogel.

The content of the I-shaped carbon aerogel graphene obtained by the method is 70%, and the content of the amorphous carbon is 30%. The oxygen element accounts for 0.2 atomic percent and is extremely high-degree reduced carbon aerogel. All have omni-directional compressible super-elasticity, and the recoverable compression strain along different directions is 97-99%. The strength is greater than 700 kPa. The density is 50mg/cm³The conductivity is more than 100S/m. The ratio of the amount of the heavy substances to the weight of the heavy substances is 30 ten thousand. Compared with graphene aerogel of composite carbon nano tubes, PDMS and PPY, the carbon aerogel prepared by the method has omnidirectional compressibility and superelasticity, and is more excellent in strength and conductivity.

Specific example 8:

step (a) 10 parts by mass of graphene oxide and 10 parts by mass of maltose are dispersed in 500 parts by mass of water to form a graphene oxide and additive dispersion liquid.

And (b) injecting the graphene oxide and maltose dispersion liquid into an O-shaped mold for vacuum drying to obtain the O-shaped graphene oxide aerogel containing the additive.

And (c) carrying out heat treatment on the O-shaped graphene oxide aerogel containing the additive for 400h at 1700 ℃ under the protection of a nitrogen atmosphere to obtain the O-shaped carbon aerogel.

The O-shaped carbon aerogel graphene obtained by the method accounts for 30% and the amorphous carbon accounts for 70%. The oxygen element accounts for 0.01 percent of the atomic percent and is extremely high-degree reduced carbon aerogel. All have omni-directional compressible super-elasticity, and the recoverable compression strain along different directions is 20 to 80 percent. The strength is greater than 700 kPa. The density is 10mg/cm³The conductivity is more than 100S/m. The ratio of the amount of heavy materials to the weight of the heavy materials is 40 ten thousand. Compared with graphene aerogel of composite carbon nano tubes, PDMS and PPY, the carbon aerogel prepared by the method has omnidirectional compressibility and superelasticity, and is more excellent in strength and conductivity.

Specific example 9:

step (a) disperses 20 parts by mass of graphene oxide and 20 parts by mass of cellulose into 500 parts by mass of dimethylformamide to form a graphene oxide and additive dispersion liquid.

And (b) injecting the graphene oxide and the cellulose dispersion liquid into a cubic mold for common thermal drying to obtain the cubic graphene oxide aerogel containing the additive.

And (c) carrying out heat treatment on the cubic graphene oxide aerogel containing the additive for 4 hours at the temperature of 600 ℃ under the protection of nitrogen atmosphere to obtain the carbon aerogel.

The cubic carbon aerogel graphene obtained by the method accounts for 50% and the amorphous carbon accounts for 50%. The oxygen element accounts for 30 atomic percent and is slightly reduced carbon aerogel. All have omni-directional compressible super-elasticity, and the recoverable compression strain along different directions is 87-99.9%. The strength is greater than 700 kPa. The density is 0.2mg/cm³The conductivity is more than 100S/m. The ratio of the amount of the heavy substances to the weight of the heavy substances is 50 ten thousand. Compared with graphene aerogel of composite carbon nano tubes, PDMS and PPY, the carbon aerogel prepared by the method has omnidirectional compressibility and superelasticity, and is more excellent in strength and conductivity.

Specific example 10:

step (a) 50 parts by mass of graphene oxide and 50 parts by mass of raffinose are dispersed in 500 parts by mass of ethanol to form a graphene oxide and additive dispersion liquid.

And (b) injecting the graphene oxide and raffinose dispersion liquid into a film-shaped mold for supercritical drying to obtain the film-shaped graphene oxide aerogel containing the additive.

And (c) carrying out heat treatment on the thin-film graphene oxide aerogel containing the additive for 4h at 500 ℃ under the protection of nitrogen atmosphere to obtain the thin-film carbon aerogel.

The thin-film carbon aerogel graphene obtained by the method accounts for 80% and the amorphous carbon accounts for 20%. The oxygen element accounts for 40 atomic percent and is slightly reduced carbon aerogel. All have omni-directional compressible super-elasticity, and the recoverable compression strain along different directions is 80-85%. The strength is greater than 700 kPa. The density is 2mg/cm³The conductivity is more than 100S/m. The ratio of the amount of the heavy substances to the weight of the heavy substances is 5 ten thousand. Compared with graphene aerogel of composite carbon nano tubes, PDMS and PPY, the carbon aerogel prepared by the method has omnidirectional compressibility and superelasticity, and is more excellent in strength and conductivity.

Specific example 11:

step (a)5 parts by mass of graphene oxide and 5 parts by mass of lactose are dispersed in 500 parts by mass of ethanol to form a graphene oxide and additive dispersion liquid.

And (b) injecting the graphene oxide and lactose dispersion liquid into a hexagonal cylindrical mold for hot drying to obtain the hexagonal cylindrical graphene oxide aerogel containing the additive.

And (c) carrying out heat treatment on the hexagonal cylindrical graphene oxide aerogel containing the additive for 4 hours at 900 ℃ under the protection of nitrogen atmosphere to obtain the hexagonal cylindrical carbon aerogel.

The hexagonal-column-shaped carbon aerogel graphene obtained by the method accounts for 60% and the amorphous carbon accounts for 40%. The oxygen element accounts for 13 atomic percent and is the moderate reduced carbon aerogel. All have omnidirectional pressableContractible elasticity, recoverable compressive strain in different directions is 60% -95%. The strength is more than 500 kPa. The density is 3mg/cm³The conductivity is more than 100S/m. The ratio of the amount of heavy materials to the weight of the heavy materials is 15 ten thousand. Compared with graphene aerogel of composite carbon nano tubes, PDMS and PPY, the carbon aerogel prepared by the method has omnidirectional compressibility and superelasticity, and is more excellent in strength and conductivity.

Specific example 12:

step (a) disperses 5 parts by mass of graphene oxide and 5 parts by mass of glucose into 500 parts by mass of water to form a graphene oxide and additive dispersion liquid.

And (b) injecting the graphene oxide and glucose dispersion liquid into a spherical mold for supercritical drying to obtain the spherical graphene oxide aerogel containing the additive.

And (c) carrying out heat treatment on the spherical graphene oxide aerogel containing the additive for 4h at 1200 ℃ under the protection of nitrogen atmosphere to obtain spherical carbon aerogel.

And (d) cutting the spherical carbon aerogel to obtain the two-dimensional lamellar carbon aerogel with the thickness of 1 nm.

The two-dimensional lamellar carbon aerogel graphene obtained by the method accounts for 95% and the amorphous carbon accounts for 5%. The oxygen element accounts for 0.8 atomic percent and is highly reduced carbon aerogel. The elastic sheet has super elasticity along the in-plane direction of the sheet layer, and the recoverable compression strain along different directions is 98-99.9%. The strength is more than 500 kPa. The density is 3mg/cm³The conductivity is more than 100S/m. The ratio of the amount of the heavy substances to the weight of the heavy substances is 30 ten thousand. Compared with graphene aerogel of composite carbon nano tubes, PDMS and PPY, the carbon aerogel prepared by the method has omnidirectional compressibility and superelasticity, and is more excellent in strength and conductivity.

Specific example 13

Referring to fig. 6, a central copper electrode is disposed on the spherical elastic conductive graphene composite carbon nanotube aerogel, and a free electrode capable of moving in any direction is disposed on the surface of the aerogel, so that pressure in any direction in a three-dimensional space can be detected.

The obtained touch sensor for medium pressure has the working range of more than 100kPa, the sensitivity of 2/kPa and the energy consumption of less than 30 muW, and can detect the pressure in any direction in three-dimensional space.

In other embodiments provided herein, the carbon aerogel can be regular or irregular in shape; the electrodes may be flexible or rigid; the electrode material is other materials which do not react with the aerogel, the position and number of the electrode can be changed, the working range of the touch and pressure sensor is wide, and optionally, the touch and pressure sensor comprises: 1) less than or equal to 15Pa, 2) greater than or equal to 15Pa, 3)15Pa-200Pa, 4)200Pa-10kPa, 5)100Pa-5kPa, 6) greater than 10kPa, and 7) greater than 100 kPa. The number of detectable pressures can be any positive integer, and the direction can be any direction along the three-dimensional space.

EXAMPLES example 14

Referring to fig. 7, two free electrodes capable of moving in any direction are disposed on the surface of the spherical elastic conductive graphene composite carbon nanotube aerogel, so as to detect pressure in any direction in a three-dimensional space.

In other embodiments provided herein, the carbon aerogel can be regular or irregular in shape; the electrodes may be flexible or rigid; the electrode is made of other materials which do not react with the aerogel, the position and the number of the electrodes are variable, and the working ranges of the touch and pressure sensor optionally include 1) less than or equal to 15Pa, 2) more than 15Pa, 3)15Pa-200Pa, 4)200Pa-10kPa, 5)100Pa-5kPa, 6) more than 10kPa, and 7) more than 100 kPa. The sensitivity and the energy consumption are adjustable. The output electric signal can be one or more of resistance, current and voltage. The number of detectable pressures can be any positive integer, and the direction can be any direction along the three-dimensional space.

Specific example 15

Referring to fig. 8, gold electrodes polished by sand paper are arranged on cylindrical elastic conductive carbon nanotube aerogel, the area of the gold electrodes is slightly smaller than the surface of the aerogel, a certain interval is formed between the gold electrodes, the gold electrodes are wrapped on the surface of a cylinder, eight electrodes are arranged in total, one electrode is arranged in the center of the gold electrodes and serves as a fixed electrode, and pressure in 8 directions can be detected.

The obtained tactile sensor for medium pressure has the working range of 15Pa-200Pa, the sensitivity of 10/kPa, the energy consumption of less than 30 muW and can detect 8 different forces in 8 directions.

EXAMPLE 16

Referring to fig. 9, gold electrodes polished by sand paper are arranged on the cylindrical elastic conductive carbon nanotube aerogel, the area of the gold electrodes is slightly smaller than the surface of the aerogel, a certain interval is formed between the gold electrodes, the gold electrodes are wrapped on the surface of the cylinder, six electrodes are arranged in total, one electrode is arranged in the center of the gold electrodes and serves as a fixed electrode, and pressure in 6 directions can be detected.

The obtained touch sensor for medium pressure has the working range of 15Pa-200Pa, the sensitivity of 10/kPa and the energy consumption of less than 30 μ W, and can detect different forces in 6 directions.

Specific example 17

Referring to fig. 10, gold electrodes polished by sand paper are arranged on the cylindrical elastic conductive carbon nanotube aerogel, the area of the gold electrodes is slightly smaller than the surface of the aerogel, a certain interval is formed between the gold electrodes, the gold electrodes are wrapped on the surface of the cylinder, and the pressure in 8 directions can be detected.

Detailed description of example 18

Referring to fig. 11, gold electrodes polished by sand paper are arranged on cylindrical elastic conductive carbon nanotube aerogel, the area of the gold electrodes is slightly smaller than the surface of the aerogel, a certain interval is formed between the gold electrodes, the gold electrodes are wrapped on the surface of a cylinder, and the total of six gold electrodes can detect the pressure in 6 directions.

Specific example 19

Referring to fig. 12, carbon nanotube thin film electrodes are disposed on the carbon nanotube composite graphene aerogel with elastic and conductive thin film, the area of the carbon nanotube thin film electrodes is slightly smaller than the surface of the aerogel, and the carbon nanotube thin film electrodes are disposed up and down, one in left and right, and one in left and right, respectively, and can detect pressure in two directions.

The obtained touch sensor for small pressure has the working range of 15Pa-200Pa, the sensitivity of 10/kPa and the energy consumption of less than 30 muW, and can detect different forces in two directions.

Detailed description of example 20

The gold electrode ground by abrasive paper is arranged on the cubic elastic conductive carbon nanotube composite polyvinyl alcohol aerogel, the area of the gold electrode is slightly smaller than the surface of the aerogel, a certain interval is reserved between the gold electrode and the aerogel, the gold electrode is wrapped on the surface of a cube, and six gold electrodes can detect the pressure in 6 directions.

The obtained touch sensor for small pressure has the working range of 15Pa-200Pa, the sensitivity of 10/kPa, the energy consumption of less than 30 muW, and can detect different forces in 6 directions.

Detailed description of example 21

Step a) preparing cubic carbon aerogel, which is prepared by the aerogel preparation method.

And b) arranging gold electrodes polished by abrasive paper on the cubic carbon aerogel, wherein the area of each gold electrode is slightly smaller than the surface of the graphene aerogel, and the gold electrodes are symmetrically arranged up and down, left and right, and can detect the pressure in two directions.

The obtained tactile and pressure sensor for medium pressure has the working range of 200Pa-10kPa, the sensitivity of 2/kPa, the energy consumption of less than 30 muW, can detect different forces in two directions, and the output electric signal is resistance.

Detailed description of the preferred embodiment 22

Step a) preparing a cylindrical carbon aerogel, which is prepared by the aerogel preparation method.

Step b) arranging gold electrodes polished by abrasive paper on the cylindrical carbon aerogel, wherein the area of the gold electrodes is slightly smaller than the surface of the graphene aerogel, a certain interval is reserved between the gold electrodes and the graphene aerogel, the gold electrodes are wrapped on the surface of the cylinder, the number of the gold electrodes is eight, one electrode is arranged in the center of the gold electrodes and serves as a fixed electrode, and pressure in 8 directions can be detected.

The obtained tactile and pressure sensor for medium pressure has the working range of 200Pa-10kPa, the sensitivity of 2/kPa, the energy consumption of less than 30 muW, and can detect different forces in 8 directions, and the output electric signal is current.

Detailed description of example 21

Step b) arranging copper electrodes on the cubic carbon aerogel, wherein the area of each copper electrode is slightly smaller than the surface of the graphene aerogel, and the copper electrodes are symmetrically arranged up and down, one is symmetrically arranged left and right, and the other is symmetrically arranged left and right, as shown in fig. 6

It is shown that pressure in two directions can be detected.

The obtained tactile and pressure sensor for large pressure has the working range of more than 10kPa, the sensitivity of 0.02/kPa and the energy consumption of less than 30 muW, can detect different forces in two directions, and outputs an electric signal as voltage.

Detailed description of the preferred embodiment 22

Step b) arranging silver electrodes polished by abrasive paper on the cylindrical carbon aerogel, wherein the area of the silver electrodes is slightly smaller than the surface of the graphene aerogel, a certain interval is reserved between the silver electrodes, the silver electrodes wrap the surface of the cylinder, the number of the silver electrodes is eight, one electrode is arranged in the center of the silver electrodes and serves as a fixed electrode, and pressure in 8 directions can be detected.

The obtained sensor has the advantages of high isopressure, working range of more than 10kPa, sensitivity of 0.02/kPa, energy consumption of less than 30 muW, capability of detecting different forces in 8 directions, and output electric signal of resistance.

Specific example 23

Step a) preparing a thin film-shaped carbon aerogel, which is prepared by the aerogel preparation method.

And b) arranging graphene film electrodes on the film-type carbon aerogel, wherein the area of each graphene film electrode is slightly smaller than the surface of the graphene aerogel, and the graphene film electrodes are symmetrically arranged up and down respectively and can detect the pressure in two directions.

Detailed description of example 24

And b) arranging gold electrodes on the cubic carbon aerogel, wherein the area of the gold electrodes is slightly smaller than the surface of the graphene aerogel, and the gold electrodes are arranged in an up-down, front-back and left-right symmetrical mode and can detect the pressure in three symmetrical directions.

The obtained touch sensor for small pressure has the lower detection limit of less than or equal to 15Pa, the sensitivity of 10/kPa and the energy consumption of less than 30 muW, can detect different forces in two directions, and outputs an electric signal as resistance.

EXAMPLE 25

The obtained sensor has the advantages of medium pressure, working range of 100Pa-5kPa, sensitivity of 0.02/kPa, energy consumption of less than 30 μ W, capability of detecting 8-direction different forces, and output electric signal of resistance.

Detailed description of example 26

And b) arranging copper electrodes on the cubic carbon aerogel, wherein the area of each copper electrode is slightly smaller than the surface of the graphene aerogel, and the copper electrodes are symmetrically arranged up and down, and are symmetrically arranged left and right, so that the pressure in two directions can be detected.

The obtained tactile and pressure sensor for large pressure has the working range of more than 100kPa, the sensitivity of 20/kPa and the energy consumption of less than 30 muW, can detect different forces in two directions, and outputs an electric signal as voltage.

Specific example 27

And b) arranging graphene film electrodes on the cubic carbon aerogel, wherein the area of each graphene film electrode is slightly smaller than the surface of the graphene aerogel, and the graphene film electrodes are symmetrically arranged up and down, one is symmetrically arranged left and right, and the pressure in two directions can be detected.

The obtained touch sensor is an all-carbon and pressure touch sensor for large pressure, the working range is more than 100kPa, the sensitivity can reach 20/kPa, the energy consumption is lower than 30 muW, different forces in two directions can be detected, and the output electric signal is voltage. The all-carbon touch and pressure sensor can work in extremely harsh environments, including extremely low temperatures. Is resistant to corrosion by acid, alkali and salt.

Detailed description of example 28

Step a) preparing cylindrical carbon aerogel, which is prepared by the sponge preparation method.

Step b) arranging gold electrodes 3 which are polished by abrasive paper on a cylindrical carbon sponge 4, wherein the area of the gold electrodes is slightly smaller than the surface of the sponge, a certain interval is reserved between the gold electrodes and the sponge, the gold electrodes are wrapped on the surface of the cylinder, the total number of the gold electrodes is six, one electrode 1 is arranged at the central part of the gold electrodes and serves as a fixed electrode, the electrodes and aerogel are bonded by conductive silver adhesive, and pressure in 6 directions can be detected.

The touch sensor for medium pressure is obtained, the working range is large and adjustable, the sensitivity is large and adjustable, the power consumption is lower than 30 muW, and 6 different forces can be detected.

In other embodiments provided herein, the carbon aerogel can be regular or irregular in shape; the electrodes may be flexible or rigid; the electrode is made of other materials which do not react with the carbon sponge, the position and the number of the electrodes are variable, the working range of the touch and pressure sensor is wide, and the working range of the touch and pressure sensor optionally comprises 1) more than 15Pa, 2)15Pa-200Pa, 3)200Pa-10kPa, 4)100Pa-5kPa, 5) more than 10kPa, and 6) more than 100 kPa. The sensitivity and the energy consumption are adjustable. The output electric signal can be one or more of resistance, current and voltage. The number of detectable pressures can be any positive integer, and the direction can be any direction along the three-dimensional space.

In other embodiments provided by the present invention, in the method for preparing a carbon aerogel, the additive is one or more of monosaccharide, disaccharide, oligosaccharide or polysaccharide; the proportion of the additive and the graphene oxide is adjustable at will; the dispersant can be water and an organic solvent; the heat treatment temperature can be changed within the range of 200 ℃ and 2500 ℃; the graphene proportion of the obtained carbon aerogel is adjustable within the range of 10% -90%; the proportion of oxygen element is adjustable within 0.1-60%, and the rest elements are carbon elements and do not contain other elements; the recoverable strain is adjustable within 0.1-99.9%; the density is 0.2mg/cm³-200mg/cm³The range is adjustable. In the method for preparing the sensor, the carbon aerogel can be in a regular or irregular shape; the electrodes may be flexible or rigid; the electrode is made of other materials which do not react with the carbon aerogel, the position and the number of the electrodes are variable, the working range of the touch and pressure sensor is large, and the working range of the touch and pressure sensor optionally comprises 1) less than or equal to 15Pa, 2) more than 15Pa, 3)15Pa-200Pa, 4)200Pa-10kPa, 5)100Pa-5kPa, and 6) more than 10 kPa. 7) Greater than 100 kPa. The sensitivity and the energy consumption are adjustable. The output electric signal can be one or more of resistance, current and voltage. The number of detectable pressures can be any positive integer, and the direction can be any direction along the three-dimensional space.

The invention provides a carbon aerogel and a preparation method thereof, and also provides two types of pressure sensors, wherein the carbon aerogel has omnidirectional compressible superelasticity, omnidirectional recoverable compressibility, high strength and high conductivity, and can be used for constructing novel compression-resistant electronic devices such as flexible batteries, supercapacitors, sensors, brakes and the like. Can also be used as a carbon biological tissue scaffold, an ultralight mechanical damping porous material and an ultralight heat/sound insulation porous material. The method for preparing the carbon aerogel does not need the step of chemical vapor deposition, so that complex chemical vapor deposition equipment is not needed, the preparation method is simple and convenient, and the cost is low. The touch and pressure sensor based on the omnidirectional compressible super-elasticity, high-strength and high-conductivity carbon aerogel and capable of detecting the pressure in any direction not only enlarges the working range of the sensor and improves the working capacity, but also reduces the arrangement cost of the sensor, has low detection lower limit and high sensitivity, and is suitable for being used as a touch sensor for monitoring human health signals and mechanically simulating hands. In particular, when a conductive carbon material such as carbon nanotube or graphene is used as an electrode and a wire, an all-carbon sensor can be prepared. The all-carbon sensor has the characteristics of light weight, wide working temperature range, acid and alkali resistance and salt corrosion resistance, and has wide application prospects in special occasions requiring touch and pressure detection, such as aerospace, strong corrosion environments and the like.

Thus, it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been illustrated and described in detail herein, many other variations or modifications consistent with the principles of the invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.

Claims

1. The carbon aerogel is characterized in that graphene or partially reduced graphene oxide and amorphous carbon are constructed and formed through a brick mud structure; the brick mud structure is a porous network-shaped composite structure which is similar to a brick mud structure and is formed by linking graphene or partially reduced graphene oxide and amorphous carbon, wherein the single-layer or multiple-layer graphene or partially reduced graphene oxide is used as a brick, and the amorphous carbon is used as a mud to coat or partially coat the graphene or partially reduced graphene oxide; the weight percentage of the components is as follows: 0.1-99.9% of graphene or partially reduced graphene oxide and 0.1-99.9% of amorphous carbon;

the carbon aerogel has compressible super elasticity, recoverable compressibility and electrical conductivity;

the carbon aerogel has omnidirectional compressible super-elasticity, omnidirectional recoverable compressibility and electrical conductivity;

wherein, the omnidirectional compressible superelasticity means that the carbon aerogel can be restored to the original length when the pressure is removed after being compressed along any direction; the omnidirectional recoverable compressibility refers to that the carbon aerogel can recover more than 60% of the original length when the pressure is removed after being compressed in any direction; the ratio of the amount of heavy substances which can be borne by the carbon aerogel to the weight of the carbon aerogel is more than 5.1 ten thousand; the carbon aerogel is macroscopically in the form of a porous foam of any geometric shape; the carbon aerogel can be machined or cut into any geometric shape.

2. The carbon aerogel of claim 1, wherein said carbon aerogel formed of graphene and amorphous carbon consists of elemental carbon; the carbon aerogel formed by partially reduced graphene oxide and amorphous carbon, which consists of oxygen and carbon elements;

3. The preparation method of the compressible super-elastic carbon aerogel is characterized by comprising the following steps of:

dispersing a saccharide additive and graphene oxide into a solvent to form a graphene oxide and additive mixed solution;

drying the graphene oxide and additive mixed solution to obtain an additive-containing graphene oxide aerogel;

carrying out high-temperature heat treatment on the graphene oxide aerogel containing the additive under the protection of inert gas to obtain carbon aerogel or all-carbon aerogel;

4. The preparation method according to claim 3, wherein the additive is one or more of monosaccharide, disaccharide, oligosaccharide or polysaccharide;

the monosaccharide is one or more of glucose, fructose, galactose and ribose;

the disaccharide is one or more of maltose, sucrose and lactose;

the oligosaccharide is one or more of raffinose and stachyose;

the polysaccharide is one or more of starch, cellulose, glycogen and xylose.

5. The production method according to claim 3, wherein the solvent is used for dispersing the additive and the graphene oxide, and the solvent includes water and an organic solvent;

the solvent is one or a mixture of water, ethanol, acetone, dimethylformamide and carbon tetrachloride.

6. The production method according to claim 3,

the method for drying the graphene oxide and additive mixed solution is one or more of freeze drying, supercritical drying, vacuum drying and normal-pressure heat drying.

7. The production method according to claim 3, wherein the temperature range of the high-temperature heat treatment is not limited, and the time of the high-temperature heat treatment is not limited;

the temperature range of the high-temperature heat treatment is 200-2500 ℃;

the time of the high-temperature heat treatment is 0.1-100 h.

8. The touch and pressure sensor is characterized by being used for detecting the touch and pressure of the carbon aerogel in any direction; the structure is as follows: the carbon aerogel of claim 1 or 2, an electrode in contact with the carbon aerogel, and a measuring device that measures an electrical signal between the electrode and the carbon aerogel.