WO2021219207A1

WO2021219207A1 - Monitorable energy-generating system

Info

Publication number: WO2021219207A1
Application number: PCT/EP2020/061806
Authority: WO
Inventors: Sachin KINGE
Original assignee: Toyota Motor Europe
Priority date: 2020-04-28
Filing date: 2020-04-28
Publication date: 2021-11-04
Also published as: DE112020007128T5

Abstract

The present invention relates to a monitorable energy-generating system comprising: - an energy-generating device comprising component parts; - at least one quantum sensor(s), preferably spin sensor(s) and most preferably nitrogen vacancy diamond (NVD) materials; - a source of irradiation configured to provide excitation to the quantum sensor(s); and - a detector configured to receive irradiation emitted by the quantum sensor(s), wherein the at least one quantum sensor(s) are located within at least one of the component parts of the energy generating device.

Description

Monitorable energy-generating system

Field of the invention

[0001] The present invention relates to a monitorable energy-generating system capable of in-situ measurement of an energy-generating device constituting part of the monitorable energy-generating system, the energy generating device containing, within at least one of its component parts, quantum sensors, which may be in the form of sub-micron particles. Background art

[0002] Clean energy technologies, such as fuel cells, lithium batteries and thermoelectric devices, are important for the environment, since they can be applied in several industrial sectors, such as stand-alone energy generation, applications in the transport sector, mass scalable devices and industrial-scale energy generators. These various types of energy technologies typically comprise, in common, one or more of electrodes, catalysts, membranes and electrolytes in combination.

[0003] For mass-scalable applications, research has been continuously carried out for developing new materials. One of the challenges during development or post-sell quality control, will be the analysis/monitoring of the internal working conditions of these devices, since it is important to detect in advance possible problems that could lead to failure of the devices and provoke safety problems. For this purpose, parameters such as temperature, electric field, magnetic field need to be monitored continuously. [0004] Conventional approaches are often time-consuming, space-consuming and/or limited in their capacity of monitoring. For example, in order to obtain information about different parts of an energy generating device, it is often necessary to first decompose/separate the devices into components and then to study the state of each component with an external technique, such as Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM) or Scanning Electron Microscopy (SEM). This is a quite time-consuming and destructive approach. Also, in order to measure temperatures of different parts of an energy generating device continuously, it is possible to insert temperature-monitoring sensors into the devices. Flowever, this might require modifications of configuration, since the conventional temperature-monitoring sensors are space-consuming. Further, these conventional sensors are often limited in their capacity of monitoring and cannot detect nano-scale information or in-situ information about the devices.

[0005] For example, Patent Literature 1 (CN 208 368 629) discloses a fuel cell monitoring device which detects a fuel cell's operational aspects, such as current, voltage and temperature. Here, the sensors are space-consuming, and it is not possible to obtain atomic-scale or nano-scale information about the fuel cell.

[0006] Patent Literature 2 discloses a fuel battery cell monitoring device, provided with a support plate having a form of comb tooth, the support plate supporting measuring terminals of plural cells, for measuring voltage and temperature. Here also, the sensor is rather space-consuming, and it is not possible to obtain atomic-scale or nano-scale information about the fuel battery cell.

[0007] Non-Patent Literature 1 discloses a thin-film multi-junction thermocouple array for in-situ multi-point simultaneous temperature measurements of a solid oxide fuel cell. Here also, although, in-situ measurement is possible, the sensor is rather space-consuming, and it is not possible to obtain atomic-scale or nano^¬ scale information about the fuel battery cell.

[0008] Spin sensors may in principle allow one to detect atomic-scale or nano^¬ scale local environment via the sensibility of spins thereto. Since the detection of spin state is made with optical techniques, spin sensors work in a non- contact mode. Some technologies such as spin polarized scanning tunneling microscopy use spin in scanning. However such techniques cannot be deployed inside a battery or fuel cells.

[0009] NV centres are point defects in diamond lattice. They consist of a substitutional nitrogen (N) atom coupled with a vacancy (V) in one of its eight nearest neighboring sites of the diamond crystal lattice. It can be in a charged state such as N-V (0) and N-V (-1). N-V(0) has an unpaired electron; in the N-V(-l) case the extra electron is at a vacancy site. The N-V(-l) state is commonly called an N-V centre and is very sensitive to spin detection.

[0010] An NV center can be detected using photoluminescence and the electron spin of the NV center is sensitive to electric field, magnetic field, radiations, heat, strain etc. The optical spectra of such center consists of sharp lines in the MHz and GHz range, and these can give information about the changes in the NV center due to external fields.

[0011] NV diamond sensors are a kind of spin sensor, using synthetic diamonds wherein nitrogen-vacancy can be created by a method known in the art, for example by using ion implantation techniques (i.e. ion irradiation followed by subsequent annealing), as described in Non-patent Literature 2.

[0012] Patent Literature 3 discloses a system for magnetic detection comprising a nitrogen vacancy (NV) diamond material comprising a plurality of NV centres, a radiofrequency (RF) excitation source configured to provide RF excitation to the NV diamond material that changes the population of sub-bands within energy states which are separated due electric/magnetic/temperature/strain fields, an optical excitation source (laser) configured to provide optical excitation to the NV diamond material, an optical detector configured to receive an optical signal emitted by the NV diamond material and a controller.

[0013] However, Patent Literature 3 discloses an application merely for monitoring the magnetic field, and application to an energy-generating device (such as fuel cells, lithium batteries, thermoelectric devices etc.) has never been disclosed. [0014] The present invention provides a monitorable energy generating system comprising a spin sensor, and in particular a NV diamond sensor. The present invention allows one to obtain atomic-scale or nano-micro scale information on the state of electrodes, membranes, catalyst systems and other locations of interest to monitor the conditions of the target device, such as fuel cells, batteries, thermoelectric devices etc.

[0015] Non-Patent Literature 3 illustrates the formation kinetics of NV centers in diamond and their transformation from one charge state to another.

[0016] Non-Patent Literature 4 demonstrates highly-tunable formation of nitrogen-vacancy (NV) centers using 20 keV 15N+ ion implantation through arrays of high-resolution apertures fabricated with electron beam lithography.

Non-patent literature

[0017] Non-patent Literature 1: Manoj et al., M. Ranaweera, I. Choi and J. Kim, "Cell integrated thin-film multi-junction thermocouple array for in-situ temperature monitoring of solid oxide fuel cells," 2015 IEEE SENSORS, Busan, 2015, pp. l-4.doi: 10.1109/ICSENS.2015.7370102

[0018] Non-patent Literature 2: Schwartz J., Aloni S., Ogletree D. F., Schenke T., "Effects of low-energy electron irradiation on formation of nitrogen-vacancy centers in single-crystal diamond", New J. Phys. 2012, 14, 043024.

[0019] Non-Patent Literature 3: A. Haque, S. Sumaiya, "An overview on the Formation and Processing of Nitrogen-Vacancy Photonic Centers in Diamond by Ion Implantation", J. Manuf. Mater. Process. 2017, 1, 6 [0020] Non-Patent Literature 4: S. Sangtawesin, T. O. Brundage, Z. J. Atkins and J. R. Petta, "Highly-tunable formation of nitrogen-vacancy centers via ion implantation", Appl. Phys. Lett. 105, 063107 (2014)

Patent Literature

[0021] Patent Literature 1: CN 208 368 629 U Patent Literature 2: JP 2006 140 166 Patent Literature 3: WO 2016/118791 A1

Brief description of the drawings [0022] Fig. 1 presents an NV diamond structure.

Fig. 2 presents a sensor architecture for in-situ analysis, wherein a) represents nano-diamonds of a size of 1-100 nm with one or multiple NV centers added or attached to the substrate of choice, at random or at predetermined positions, b) represents a (microwave) RF source which provides excitation to NV centres, equipped with a laser source, c) represents a collector of fluorescent light emitted from the NV centers via confocal microscopy, and d) represents a control unit equipped with a computer.

Fig. 3 presents how the desired local information at nano-micro scale can be monitored by using spin sensors.

Detailed description of the invention

[0023] The monitorable energy-generating system of the present invention comprises:

- an energy-generator comprising, within at least one of its component parts, one or more quantum sensors;

- a source of irradiation configured to provide excitation to the quantum sensor(s); and

- a detector configured to receive irradiation emitted by the quantum sensor(s). [0024] In one embodiment the quantum sensor is a spin sensor, and in particular an NVD sensor.

[0025] The monitorable energy-generating system of the present invention allows one to obtain micro-nano scale in-situ information of the status of an energy-generating device, without destroying the device, and therefore provides a method of monitoring which is not time-consuming or space consuming.

Energy-generator

[0026] An energy generator is a device which generates energy in any form. An energy generator can be, for example, a lithium battery, a fuel cell or a thermoelectric generator.

[0027] According to an embodiment of the present invention, an energy generator can comprise, one or more of:

- electrodes;

- catalysts;

- membranes; and

- an electrolyte combination.

[0028] Lithium batteries are primary batteries that have metallic lithium as an anode. These types of batteries are also referred to as lithium-metal batteries. [0029] A lithium battery can comprise:

- a cathode containing a positive-electrode active material;

- an anode normally containing lithium; and

- an electrolyte medium arranged between the cathode and the anode.

[0030] In embodiments of the present invention wherein the energy generator is a lithium battery, the quantum sensors, such as spin sensors and most preferably NVD sensors can be integrated anywhere in the lithium battery, such as in the negative electrode active material layer, the positive electrode active material layer, or in the electrolyte, membranes, separators or device casings.

> Cathode [0031] A positive electrode active material in a lithium battery can comprise, for example, heat-treated manganese dioxide; carbon monofluoride; iron disulfide; thionyl chloride; thionyl chloride with bromine chloride; sulfuryl chloride; sulfur dioxide on Teflon®-bonded carbon; iodine that has been mixed and heated with poly-2-vinylpyridine (P2VP) to form a solid organic charge transfer complex; silver chromate, silver oxide + vanadium pentoxide (SVO); copper (II) oxide; copper oxyphosphate; copper sulfide; lead sulfide and copper sulfide; iron sulfide, lead bismuthate; bismuth trioxide; vanadium pentoxide; copper chloride; manganese dioxide; vanadium pentoxide; and selenium.

> Anode

[0032] An anode in a lithium battery most commonly comprises lithium.

> Electrolyte medium [0033] An electrolyte medium in a lithium battery can be, for example, lithium perchlorate in an organic solvent (propylene carbonate and dimethoxyethane in many common cells); lithium tetrafluoroborate in propylene carbonate, dimethoxyethane, or gamma-butyrolactone; propylene carbonate, dioxolane, dimethoxyethane; lithium tetrachloroaluminate in thionyl chloride; lithium tetrachloroaluminate in thionyl chloride; lithium bromide in sulfur dioxide with small amount of acetonitrile; a solid monomolecular layer of crystalline lithium iodide that conducts lithium ions from the anode to the cathode but does not conduct iodine; lithium perchlorate solution; lithium hexafluorophosphate or lithium hexafluoroarsenate in propylene carbonate with dimethoxyethane; lithium perchlorate dissolved in dioxolane; lithium metal; propylene carbonate, dioxolane, dimethoxyethane; LiAICU or LiGaCU in SO2, a liquid, inorganic, non- aqueous electrolyte; non-aqueous carbonate electrolytes; and organic, aqueous, glass-ceramic (polymer-ceramic composites). Fuel cell

[0034] A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions.

[0035] A fuel cell can comprise:

- a negative electrode active material layer;

- a positive electrode active material layer; and

- an electrolyte.

[0036] In a preferred embodiment of the present invention, quantum sensors, such as spin sensors and most preferably NVD sensors are used in a fuel cell. The quantum sensors, such as spin sensors and most preferably NVD sensors can be integrated anywhere in the fuel cell, such as in the negative electrode active material layer, the positive electrode active material layer, in the electrolyte, membranes, separators or device casings. A preferred fuel cell to be used as energy-generating device in the present invention is a proton exchange membrane fuel cell (PEMFC). Other types of fuel cell can also however be monitored using the technology of the present invention.

> Positive electrode active material

[0037] A positive electrode active material in a fuel cell can be, for example, carbon supports, Pt particles, Nation® ionomer, and Teflon® binder.

> Negative electrode active material

[0038] A negative electrode active material in a fuel cell can be, for example, carbon supports, Pt particles, Nation® ionomer, and Teflon® binder.

> Electrolyte

[0039] An electrolyte medium in a fuel cell can be, for example, an aqueous alkaline solution, such as potassium hydroxide, polymer membrane (ionomer) such as Nafion®, Aquivion®. The electrolyte medium in a fuel cell can be also, for example, be molten phosphoric acid (H3PO4), H⁺-conducting oxyanion salt (solid acid), molten alkaline carbonate, 02-conducting ceramic oxide, H⁺- conducting ceramic oxide and a salt water.

Thermoelectric generator

[0040] A thermoelectric generator (TEG), also called a Seebeck generator, is a solid state device that converts heat flux (temperature differences) directly into electrical energy through a phenomenon called the Seebeck effect (a form of thermoelectric effect).

[0041] A thermoelectric generator can comprise thermoelectric materials (such as materials based on bismuth telluride (Bi₂Te₃), lead telluride (PbTe), and silicon germanium (SiGe), thermoelectric modules (dissimilar thermoelectric materials joined at their ends), and thermoelectric systems (heat source is thermoelectric module and heat sink is air, water).

[0042] The quantum sensors, such as spin sensors and most preferably NVD sensors can be integrated anywhere in the fuel cell, such as in the negative electrode active material layer, the positive electrode active material layer, in the electrolyte, membranes, separators or device casings.

Quantum sensor

[0043] A quantum sensor is a quantum device that responds to a stimulus. Usually this refers to a sensor which has quantized energy levels, uses quantum coherence to measure physical quantity, or uses entanglement to improve measurements beyond what can be done with classical sensors. There are four criteria for quantum sensors:

1. The system has to have discrete, resolvable energy levels.

2. One can initialize the sensor and you can perform readout (turn on and get answer). 3. One can coherently manipulate the sensor.

4. The sensor interacts with a physical quantity and has some response to that quantity.

[0044] In one embodiment, the at least one quantum sensor(s) are in the form of sub-micron size particles whose maximum particle diameter measured in any direction across their three-dimensional particle structure is less than 1 miti, and more preferably less than 500 nm, and more preferably less than 200 nm, wherein the maximum particle diameter is measured by transmission electron microscopy (TEM) or atomic force microscopy (AFM).

[0045] A quantum sensor can be, for example, a spin sensor, a nitrogen vacancy diamond (NVD) sensor, an Avalanche Photodiode (APD) sensor. Preferably, a quantum sensor is a NVD sensor, which is inert to its environment (i.e. no interaction with its environment) and therefore facilitates implementation. Also, advantageously, NVD materials are expected to be chemically inert to the reactive chemicals used in energy-generating devices containing electrodes and electrolytes such as lithium batteries and fuel cells.

NVD sensors

> Nitrogen Vacancy Diamond (NVD) sensing centre [0046] A Nitrogen Vacancy sensing center is one of numerous point defects in diamond.

[0047] In the present invention, a NVD sensing centre can be single or multiple spins and are located inside small diamond particles. These diamond particles can appropriately have a size less than 1 miti, and more preferably less than 500 nm, and more preferably less than 200 nm, these dimensions referring to the maximum particle dimension measured in any direction across the three- dimensional particle structure. The particle size of NVD sensors can be measured, for example, by transmission electron microscopy (TEM) or atomic force microscopy (AFM). Advantageously, NVD particles to be used as spin sensors within the invention have a minimum size measured in any direction across the three-dimensional particle structure of at least 1 nm. Most appropriately, NVD particles to be used as spin sensors within the invention have a minimum and maximum sizes measured in any direction across the three-dimensional particle structure of: 1 nm or more and 100 nm or less, and preferably 20 nm or more and 80 nm or less, and more preferably 30 nm or more and 70 nm, and most preferably 10 nm or more and 60 nm or less.

[0048] Diamond particles of 1 to 100 nm or 2-D diamonds in micrometers are inert. There are different advantages - if small-sized centres are available, they can be dispersed at different locations and spatial information can be obtained. [0049] In another embodiment, 2-D layers can be used as support on which the active materials can be put and several centres in the 2-D materials can do spatial mapping.

[0050] An NVD sensor can comprise the following elements, as indicated in Fig. 2: a) A nitrogen vacancy (NV) diamond material comprising one or a plurality of NV centers; b) A microwave (MW source) generation source configured to provide excitation to the NV diamond material c) An optical excitation source configured to provide optical excitation to the NV diamond material; d) An optical detector configured to receive an optical signal emitted by the NV diamond material; and e) A controller configured to detect a gradient of the optical signal. b) Radiofrequency (RF) excitation source [0051] The radiofrequency excitation source may have a frequency of 1 Megahertz or more and 1000 Gigahertz or less. Such an RF excitation source can be commercially available: for an example, an arbitrary waveform generator (AWG, Textronix AWG5014) c) Optical excitation source

[0052] The optical excitation source may have a frequency of 400nm or more and llOOnm or less. For example, a tunable laser can excite states suitable for NV centres' different selective transitions, such as 546 nm, 689 nm, 1024 nm in different NV states. Such an optical excitation source can be commercially available, for example: Newport TLB series lasers; d) Optical detector.

[0053] The optical detector can be commercially available, for example: Horiba series micros. Information collected

[0054] The following information can be collected: temperature pattern, magnetic field, electric changes, state of the stack components

Monitorable energy-generating system [0055] According to the present invention, any energy generating device can be combined with any quantum sensor, such as a spin sensor, to provide a monitorable energy-generating system of the present invention.

[0056] In one embodiment, the energy generating device has a small opening, configured to host optical fibers configured to collect and deliver desired information about the state of the energy generating device.

[0057] In particular embodiments, the energy generating device is a fuel cell or a battery device.

Claims

1. A monitorable energy-generating system comprising:

- an energy-generating device comprising component parts;

- at least one quantum sensor(s);

- a detector configured to receive irradiation emitted by the quantum sensor(s), wherein the at least one quantum sensor(s) are located within at least one of the component parts of the energy generating device.

2. The monitorable energy-generating system according to claim 1, wherein the at least one quantum sensor(s) are in the form of sub-micron size particles whose maximum particle diameter measured in any direction across their three- dimensional particle structure is less than 1 miti, and more preferably less than 500 nm, and more preferably less than 200 nm, wherein the maximum particle diameter is measured by transmission electron microscopy (TEM) or atomic force microscopy (AFM).

3. The monitorable energy-generating system according to claim 1 or 2, wherein the at least one quantum sensor(s) are spin sensor(s).

4. The monitorable energy generating system according to claim 3, wherein the spin sensor is a nitrogen vacancy diamond (NVD) material.

5. The monitorable energy generating system according to claim 4, wherein the NVD material has a maximum particle diameter of 1 nm or more and 100 nm or less, wherein the maximum particle diameter is as measured by transmission electron microscopy (TEM) or atomic force microscopy (AFM).

6. The monitorable energy generating system according to any one of claims 1 to 5, wherein NVD sensors can be integrated anywhere in the fuel cell, such as in the negative electrode active material layer, the positive electrode active material layer, in the electrolyte membranes, separators or device casings.

7. The monitorable energy generating system according to any of claims 1 to 6, wherein the source of irradiation configured to provide excitation to the at least one quantum sensor(s) is a radiofrequency (RF) excitation source or an optical excitation source such as a laser source.

8. The monitorable energy generating system according to any of claims 1 to 7, wherein the detector configured to receive irradiation emitted by the at least one quantum sensor(s) is an optical detector.

9. The monitorable energy generating system according to any one of claims 1 to 8, wherein the energy generating device is a lithium battery comprising:

- a negative electrode containing a negative-electrode active material;

- a positive electrode containing a positive electrode active material; and

- an electrolyte medium arranged between the negative electrode and the positive electrode.

10. The monitorable energy generating system according to claim 9, wherein the positive electrode active material comprises any one selected from the group consisting of heat-treated manganese dioxide; carbon monofluoride; iron disulfide; thionyl chloride; thionyl chloride with bromine chloride; sulfuryl chloride; sulfur dioxide on Teflon®-bonded carbon; iodine that has been mixed and heated with poly-2-vinylpyridine (P2VP) to form a solid organic charge transfer complex; silver chromate, silver oxide + vanadium pentoxide (SVO); copper(II) oxide; copper oxyphosphate; copper sulfide; lead sulfide and copper sulfide; iron sulfide, lead bismuthate; bismuth trioxide; vanadium pentoxide; copper chloride; manganese dioxide; vanadium pentoxide; and selenium.

11. The monitorable energy generating system according to claim 9 or 10, wherein the negative electrode active material is lithium.

12. The monitorable energy generating system according to any one of claims 7 to 9, wherein the electrolyte medium comprise at least any one selected from the group consisting of lithium perchlorate in an organic solvent such as propylene carbonate and dimethoxyethane; lithium tetrafluoroborate in propylene carbonate, dimethoxyethane, or gamma-butyrolactone; propylene carbonate, dioxolane, dimethoxyethane; lithium tetrachloroaluminate in thionyl chloride; lithium tetrachloroaluminate in thionyl chloride; lithium bromide in sulfur dioxide with acetonitrile; a solid monomolecular layer of crystalline lithium iodide; lithium perchlorate solution; lithium hexafluorophosphate or lithium hexafluoroarsenate in propylene carbonate with dimethoxyethane; lithium perchlorate dissolved in dioxolane; lithium metal; propylene carbonate, dioxolane, dimethoxyethane; LiAICU or LiGaCU in SO2; non-aqueous carbonate electrolytes; and organic, aqueous, glass-ceramic (polymer-ceramic composites).

13. The monitorable energy generating system according to any one of claims 1 to 8, wherein the energy generating device is a fuel cell comprising:

- a negative electrode active material layer;

- a positive electrode active material layer; and

- an electrolyte.

14. The monitorable energy generating system according to claim 13, wherein the negative electrode active material is selected from the group consisting of carbon supports, Pt particles, Nation® ionomer, and Teflon® binder.

15. The monitorable energy generating system according to claim 13 or 14, wherein the positive electrode active material is selected from the group consisting of carbon supports, Pt particles, Nation® ionomer, and Teflon® binder.

16. The monitorable energy generating system according to any one of claims 13 to 15, wherein the electrolyte comprises at least any one selected from the group consisting of: an aqueous alkaline solution, such as potassium hydroxide, polymer membrane (ionomer) such as Nation®, Aquivion®; molten phosphoric acid (H3PO4); H⁺-conducting oxyanion salt (solid acid); molten alkaline carbonate; 02-conducting ceramic oxide; H⁺-conducting ceramic oxide; and a salt water.

17. The monitorable energy generating system according to any one of claims 1 to 8, wherein the energy generating device is a thermoelectric generator comprising: thermoelectric materials such as materials based on bismuth telluride (Bi₂Te₃), lead telluride (PbTe), and/or silicon germanium (SiGe); thermoelectric modules in the form of dissimilar thermoelectric materials joined at their ends; and thermoelectric systems wherein the heat source is thermoelectric module and the heat sink is air, water.