There is the barium oxide and carbon composite and preparation method thereof of hierarchical porous structure
Technical field
The present invention relates to electrode material for super capacitor field, be specially a kind of barium oxide and carbon composite and preparation method thereof with hierarchical porous structure.
Background technology
The world today, resource and the energy are day by day short, the traditional energy nervous situation that supply falls short of demand and day by day serious environmental problem, make large-scale developing and utilizing of new forms of energy imperative.The new forms of energy such as solar energy, wind energy, tidal energy of current most prospect, due to the unsteadiness that intermittence and the electric energy of its generating export, be badly in need of the memory device with high-energy-density, high power density, large specific energy, in order to store and to stablize, discharge electric energy constantly.In novel environment friendly power vehicle field, be also badly in need of this type of energy storage device to meet transient high-current demand when it starts climbing, and can quick storage automobile brake time the high-power energy that produces.Novel energy-storing device ultracapacitor arises at the historic moment, and the development of it and automobile with novel power is closely related, and being vitals indispensable in renewable new energy field, is the key of New Energy Industry.But it is on the low side that the bottleneck of current ultracapacitor is still energy density, and current problem urgently to be resolved hurrily how significantly to improve the energy density of ultracapacitor.
Current ultracapacitor mainly adopts the active carbon porous electrode based on electric double layer energy storage, but its specific area practical efficiency is low.And metal oxide containing precious metals, have the performance of pseudo-capacitance, ratio capacitance is high, but this type of material specific surface area is less, unstable properties, and expensive, limits its commercialization.Therefore, the advanced composite material (ACM) based on cheap transition metal oxide is paid close attention to.
Barium oxide due to its have valence state and stoichiometry change greatly, the feature such as layer structure, high power capacity, just be used as anode material for lithium-ion batteries as far back as 1976 to be studied, but just come into one's own in recent years used as the research of electrode material for super capacitor.Barium oxide is with the redox reaction of high reversible in charge and discharge process, and produce very large fake capacitance, ratio capacitance value is high, but its large current density electrical characteristics and cycle performance poor.Since 2009, it has been reported at home and abroad that with vanadic oxide and active carbon be the research that negative pole assembles hybrid super capacitor and asymmetric super-capacitor, and infusion process prepares the research of vanadic oxide and mesoporous carbon composite electrode material.But infusion process easily causes guest particles to assemble, cause basis material duct to block, and barium oxide content is on the low side, effectively can not plays its fake capacitance advantage.In addition, the high-temperature process such as the fusing point of barium oxide is lower and activity is higher, chemical gaseous phase injection are easy to cause structure collapses and phase transition.
Up to the present, there is not yet and adopt evaporation induced self-assembly method directly to obtain having the barium oxide of hierarchical porous structure and carbon composite is reported as the pertinent literature of electrode material for super capacitor.
Summary of the invention
The object of this invention is to provide a kind of barium oxide and carbon composite and preparation method thereof with hierarchical porous structure, this composite material is as the electrode material of ultracapacitor.
Realize the technical scheme that the object of the invention adopts: a kind of barium oxide and carbon composite, it is characterized in that in this material, vanadium and carbon mass ratio are 0.4 ~ 1.5, material has hierarchical porous structure, there is macropore and mesoporous simultaneously, macropore size is at 0.2 ~ 1.5 μm, mesopore size is at 15 ~ 50nm and 2.6 ~ 5.4nm, and specific area is 105.0 ~ 413.8m
2/ g.
The preparation method of a kind of barium oxide of the present invention and carbon composite, hydrochloric acid, block copolymer, ethanol, phenolic resins and ammonium metavanadate are mixed, after evaporation induced self-assembly, obtain that there is hierarchical porous structure through thermal polymerization and charing again, have macropore and mesoporous barium oxide and carbon composite, wherein block copolymer used is EO simultaneously
100pO
70eO
100, wherein EO is oxirane, and PO is expoxy propane.
The preparation of barium oxide of the present invention and carbon composite comprises the following steps:
(1) by hydrochloric acid, block copolymer, ethanol, phenolic resins ethanolic solution in mass ratio=1.0:1.6:8.0:5.0, mix with ammonium metavanadate;
(2) mixture is transferred in flat bottom evaporating dishes,double, at room temperature evaporation induced self-assembly, again through 100 DEG C of thermal polymerizations be warming up to 700 DEG C of insulation charings in a nitrogen atmosphere, must obtain that there is hierarchical porous structure, there is macropore and mesoporous barium oxide and carbon composite simultaneously;
Wherein, in step (1), hydrochloric acid used is 0.2mol/L hydrochloric acid solution; Block copolymer used is Pluronic F-127-polycyclic oxypropylene-Pluronic F-127 class triblock copolymer, and molecular formula is EO
100pO
70eO
100, EO is oxirane, and PO is expoxy propane; The ethanolic solution of described phenolic resins is 20wt% phenolic resins ethanolic solution; Described ammonium metavanadate inventory and the mass ratio of hydrochloric acid consumption are 0.5 ~ 2.0.
In above-mentioned preparation method's step (2), 100 DEG C of hot polymerizations merge insulation 24h; Be warming up to 700 DEG C of insulation charing 3h under nitrogen protection, carbonizing the speed being warming up to 700 DEG C is 1 ~ 2 DEG C/min.
Barium oxide of the present invention and carbon composite can be used as electrode material for super capacitor.
Barium oxide of the present invention and carbon composite have hierarchical porous structure, are conducive to electronics and transmit quickly and efficiently, be suitable as electrode material for super capacitor.Barium oxide prepared by the present invention and carbon composite show in the cyclic voltammetry of three-electrode system and constant current charge-discharge research, with only use mesoporous carbon as compared with electrode, the capacitive property of barium oxide and C-C composite electrode significantly improves, and stability is better.
Preparation technology of the present invention is simple, and low for equipment requirements, operability is good, with low cost, and the exploitation for ultracapacitor new electrode materials provides new direction.
Accompanying drawing explanation
Fig. 1 is the barium oxide of embodiment 1 preparation and the XRD collection of illustrative plates of carbon composite;
Fig. 2 is the barium oxide of embodiment 1 preparation and the SEM image of carbon composite;
Fig. 3 is the barium oxide of embodiment 1 preparation and the TEM image of carbon composite;
Fig. 4 is the barium oxide of embodiment 1 preparation and the graph of pore diameter distribution of carbon composite;
Fig. 5 is the barium oxide of embodiment 1 preparation and the cyclic voltammetry curve of carbon composite electrode material.
Embodiment
The invention provides the preparation method of a kind of barium oxide and carbon composite, the method, by hydrochloric acid, block copolymer, ethanol, phenolic resins and the mixing of vanadium source, after evaporation induced self-assembly, obtains barium oxide and carbon composite through thermal polymerization and charing.The method technique is simple, and low for equipment requirements, operability is good, and prepared barium oxide and carbon composite have hierarchical porous structure, is a kind of ultracapacitor new electrode materials.Exemplify embodiment to be below further described the present invention.
Embodiment 1
A preferred embodiment in barium oxide and carbon composite preparation method, comprises the steps:
Be that the ethanolic solution of 20wt% phenolic resins mixes with 1.5g ammonium metavanadate by 1.0g hydrochloric acid solution (0.2mol/L), 1.6g block copolymer F127,8.0g ethanol, 5.0g concentration, stir 2h at 40 DEG C.Mixture is transferred in flat bottom evaporating dishes,double, at room temperature 25 DEG C, ethanol is volatilized, dark-brown film is formed after about 8h, this film is put into 100 DEG C of baking oven hot polymerizations and merge insulation 24h, 700 DEG C of charings are warming up in a nitrogen atmosphere again with the heating rate of 1 DEG C/min, naturally cool to room temperature after insulation 3h, obtain barium oxide and carbon composite.
Fig. 1 is shown in by the XRD collection of illustrative plates of product, as seen from the figure, there is V in composite material
2o
3and VO
2two kinds of thing phases.SEM image is shown in Fig. 2, and the macropore existing in composite material and be of a size of 0.4 ~ 1.3 μm is described.TEM image is shown in Fig. 3, shows to exist in composite material to be of a size of the mesoporous of 20 ~ 50nm.As shown in Figure 4, its aperture concentrates on 2.6 ~ 5.0nm to the pore-size distribution of this material as we know from the figure.Analyzed from Fig. 2, Fig. 3 and Fig. 4, composite material has hierarchical porous structure.The specific area of product is 105.0m
2/ g.
Embodiment 1 sample is mixed rear compressing tablet with the ptfe emulsion of 10wt% by 9:1 mass ratio, in 80 DEG C of vacuumizes, then under the pressure of 10MPa, this material is pressed in nickel foam, makes 1 × 1cm
2electrode.Using saturated calomel electrode as reference electrode, platinum electrode as to electrode, at 1mol/LKNO
3standard three-electrode system is formed in electrolyte.Fig. 5 is presented at the cyclic voltammetry curve under 2mV/s sweep speed, in class rectangle.When current density is 0.1A/g, the electric discharge ratio capacitance of combination electrode material is 171.0F/g.
Embodiment 2
An embodiment in barium oxide and carbon composite preparation method, step is with embodiment 1, difference is that the inventory of ammonium metavanadate and hydrochloric acid consumption mass ratio are 0.5, at room temperature 25 DEG C, make ethanol volatilize after about 8h form navy blue film, after 100 DEG C of hot polymerizations merge insulation 24h, be warming up to 700 DEG C of charings with the heating rate of 2 DEG C/min in a nitrogen atmosphere again, naturally cool to room temperature after insulation 3h, obtain barium oxide and carbon composite.SEM, TEM and pore-size distribution test show, product has macropore, meso-hole structure, and macropore size is 0.4 ~ 1.5 μm, and mesopore size is 3.5 ~ 5.4nm.XRD analysis test shows that resulting materials exists V
2o
3and VO
2two kinds of thing phases.The specific area of composite material is 413.8m
2/ g, ratio capacitance is 115.7F/g.
Embodiment 3
An embodiment in barium oxide and carbon composite preparation method, step is with embodiment 1, difference is that the inventory of ammonium metavanadate and hydrochloric acid consumption mass ratio are 2.0, at room temperature 25 DEG C, make ethanol volatilize after about 8h form brownish black film, merge after insulation 24h through 100 DEG C of hot polymerizations, be warming up to 700 DEG C of charings with the heating rate of 1.5 DEG C/min in a nitrogen atmosphere again, after naturally cooling to room temperature after insulation 3h, obtain barium oxide and carbon composite.SEM, TEM and pore-size distribution test show, product has macropore, meso-hole structure, and macropore size is 0.2 ~ 0.8 μm, and mesopore size is 2.8 ~ 4.6nm.XRD analysis test shows that resulting materials exists V
2o
3and VO
2two kinds of thing phases.The specific area of composite material is 198.2m
2/ g, ratio capacitance is 143.1F/g.