Patent Application
20170250412
The present disclosure relates to the field of electrical storage (including, for example, batteries, supercapacitors and battery-capacitor hybrids), associated methods and apparatus, and in particular concerns an apparatus comprising a graphene oxide electrode configured to generate protons in the presence of water to produce a potential difference, and an electrolyte comprising a room-temperature ionic fluid configured to absorb water from the surrounding environment and deliver said water to the electrode to facilitate the generation of protons. Certain disclosed example aspects/embodiments relate to portable electronic devices, in particular, so-called hand-portable electronic devices which may be hand-held in use (although they may be placed in a cradle in use). Such hand-portable electronic devices include so-called Personal Digital Assistants (PDAs), smartwatches and tablet PCs.
The portable electronic devices/apparatus according to one or more disclosed example aspects/embodiments may provide one or more audio/text/video communication functions (e.g. tele-communication, video-communication, and/or text transmission, Short Message Service (SMS)/Multimedia Message Service (MMS)/emailing functions, interactive/non-interactive viewing functions (e.g. web-browsing, navigation, TV/program viewing functions), music recording/playing functions (e.g. MP3 or other format and/or (FM/AM) radio broadcast recording/playing), downloading/sending of data functions, image capture function (e.g. using a (e.g. in-built) digital camera), and gaming functions.
Research is currently being done to develop smaller electrical storage cells having a greater storage capacity than existing storage cells for use in modern electronic devices.
One or more aspects/embodiments of the present disclosure may or may not address this issue.
The listing or discussion of a prior-published document or any background in this specification should not necessarily be taken as an acknowledgement that the document or background is part of the state of the art or is common general knowledge.
According to a first aspect, there is provided an apparatus comprising a first electrode, a second electrode and an electrolyte,
The first and second electrodes may be configured to form a junction with one another at an interface therebetween. The electrolyte may be in contact with the junction of the first and second electrodes.
The apparatus may be configured to allow one or both of the first electrode and electrolyte to be exposed to water in the surrounding environment.
The second electrode may comprise one or more of graphene oxide, reduced graphene oxide, potassium hydroxide, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, a base, and a conducting polymer.
The first and second electrodes may comprise first and second respective graphene oxide inks. The pH of the first graphene oxide ink may be lower than the pH of the second graphene oxide ink. The first graphene oxide ink may have a pH of 1-4 and the second graphene oxide ink may have a pH of 13-14.
The room-temperature ionic fluid may comprise one or more of a room-temperature ionic liquid and an ionic gel. The room-temperature ionic fluid may be a liquid or gel at least within one or more of the following temperature ranges: −100° C. to +100° C.; −50° C. to +50° C.; +15° C. to +35° C.; and +20° C. to +27° C.
The room-temperature ionic fluid may comprise one or more of triethylsulfonium bis(trifluoromethylsulfonyl)imide, 1-buthyl-3-methyl-imidazolium, and trioctylmethylammonium bis(trifluoromethylsulfonyl)imide.
The electrolyte may further comprise one or more salts configured to aid the flow of protons from the first electrode to the second electrode and/or enhance the adsorption of water by the room-temperature ionic fluid from the surrounding environment. The one or more salts may comprise at least one of lithium bis(trifluoromethylsulfonyl)imide, lithium chloride and sodium chloride.
The room-temperature ionic fluid may be hydrophilic and ionically conductive.
The room-temperature ionic fluid may comprise cations and anions. The cations may be substantially larger in size than the anions.
The apparatus may comprise a respective charge collector in contact with the first and second electrodes configured to provide an electrical path between the respective electrode and the external circuit. One or both of the respective charge collectors may comprise at least one of a metal, an alloy, gold, silver, copper, aluminium, steel, and indium tin oxide.
The apparatus may comprise a substrate configured to support the first and second electrodes.
The apparatus may be one or more of a battery, a capacitor, a supercapacitor, a battery-capacitor hybrid, an electronic device, a portable electronic device, a portable telecommunications device, a mobile phone, a personal digital assistant, a phablet, a tablet, a laptop computer, an electronic watch, a wireless sensor, an electrochemical sensor, a wearable device, an RFID tag, an electrochromic device, and a module for one or more of the same.
According to a further aspect, there is provided a method of making an apparatus comprising a first electrode, a second electrode and an electrolyte, the method comprising:
One or both of forming the first and second electrodes and providing the electrolyte may comprise printing the electrodes/electrolyte.
According to a further aspect, there is provided a method of producing a potential difference using an apparatus, the apparatus comprising a first electrode, a second electrode and an electrolyte,
The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated or understood by the skilled person.
Corresponding computer programs (which may or may not be recorded on a carrier) for implementing one or more of the methods disclosed herein are also within the present disclosure and encompassed by one or more of the described example embodiments.
The present disclosure includes one or more corresponding aspects, example embodiments or features in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation. Corresponding means for performing one or more of the discussed functions are also within the present disclosure.
The above summary is intended to be merely exemplary and non-limiting.
A description is now given, by way of example only, with reference to the accompanying drawings, in which:
Electrical energy storage is an important consideration for portable electronic devices. Proton batteries are currently being developed for this purpose. The energy generation mechanism of one type of proton battery involves the degradation of graphene oxide when in contact with water. The water may be contained within the battery or it may come from the surrounding environment (e.g. in the form of air humidity).
The first 102 and second 103 electrodes are deposited such that they (at least partly) overlie respective silver charge collectors 107 and form a junction 106 with one another at an interface therebetween (e.g. where the electrode materials intermix and/or overlie one another). In this example, the charge collectors 107 each have a length (l) and width (w) of 5 mm, a thickness (t) of 1 μm, and are separated from one another by 2 mm. The in-plane junction area (i.e. l×w) is therefore 10 mm2. A number of charge/discharge cycles were performed to test the electrical properties of the existing graphene oxide-based proton battery 101. The battery 101 was found to exhibit a storage capacity of up to 100 nAh and a maximum open circuit voltage of 0.6V at 30% humidity, and could be discharged with currents of between 2 nA and 80 nA.
Importantly, the electrolyte 204 comprises a room-temperature ionic fluid configured to absorb water from the surrounding environment 205 and deliver said water to the first electrode 202 to facilitate the generation of protons. This feature has been found to boost both the storage capacity and output voltage of the apparatus 201, and also allows the apparatus 201 to be discharged at higher currents (discussed in more detail later). Furthermore, in some embodiments (e.g. secondary battery, capacitor, supercapacitor or battery-capacitor hybrid) the presence of the room-temperature ionic fluid enables the apparatus 201 to be recharged within a few minutes after being fully discharged without the application of external energy. This is due to the chemical reactions between the graphene oxide of the first electrode 202 and the water from the external environment 205 which generate protons and give rise to the potential difference. In these embodiments, the apparatus 201 may therefore be recharged provided that (i) there is water present, and (ii) the graphene oxide has not been completely consumed during the previous charge cycles. In other embodiments (e.g. primary batteries), however, the apparatus 201 may not be rechargeable.
In the example shown in
The apparatus 201 may be configured to allow one or both of the first electrode 202 and electrolyte 204 to be exposed to water in the surrounding environment 205. In practice, this could be achieved (for example) by leaving the apparatus 201 uncovered/unsealed, containing the apparatus 201 within a water and/or air-permeable material if a protective casing is required, or by providing a casing for the apparatus 201 with one or more portions which are configured to be opened and closed. The ability to expose the electrolyte 204 to water in the surrounding environment 205 is necessary in order to benefit from the enhanced electrical properties of the present apparatus 201, because the water can be considered to fuel the generation of protons. In some cases, the apparatus 201 may also comprise a water source so that protons (and therefore a potential difference) can be produced even when the humidity of the surrounding environment 205 is relatively low. For example, the apparatus 201 may comprise a water-absorbing material (such as sponge) in fluid-communication with the first electrode 202 and/or electrolyte 204 for this purpose.
In the example shown in
In addition, the apparatus 201 further comprises a substrate 208 configured to support the electrodes 202, 203, electrolyte 204 and charge collectors 207. The supporting substrate 208 is particularly useful when the various components are formed using a printing process, because printable materials (e.g. inks, liquids and gels) tend not to be self-supporting, at least until they have been dried or cured.
As mentioned above, the first electrode 202 comprises graphene oxide which reacts with the water to generate protons. In the illustrated example, the second electrode 203 comprises reduced graphene oxide, but it could comprise one or more of graphene oxide, reduced graphene oxide, potassium hydroxide, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), a base, and a conducting polymer. In some examples, the first 202 and second 203 electrodes may be formed from first and second respective graphene oxide inks. In this scenario, the first graphene oxide ink would typically have a lower pH (e.g. a pH of 1-4) than the second graphene oxide ink (e.g. a pH of 13-14). The pH difference of the inks is advantageous because it encourages the transfer of protons from the first electrode 202 to the second electrode 203 via an acid-base reaction at the junction 206 of the electrodes 202, 203.
The room-temperature ionic fluid of the electrolyte 204 may be a liquid or gel at room temperature (+20° C. to +27° C.). To achieve this, the fluid may comprise cations and anions wherein the cations are substantially larger in size than the anions (e.g. having a radius which is up to 2, 3, 4, 5 or 10 times larger than that of the anions). The difference in size between the cations and anions can prevent the fluid from forming a lattice at room temperature thus enabling the electrolyte 204 to maintain its fluid state. In some cases, the room-temperature ionic fluid may also be a liquid or gel at temperatures outside of the above “room temperature” range. For example, it may be a liquid or gel at temperatures of −100° C. to +100° C., −50° C. to +50° C., and/or +15° C. to +35° C. Advantageously, the room-temperature ionic fluid would be in its liquid or gel form at all operating temperatures of the apparatus to help ensure its proton conductivity.
The electrolyte 204 may comprise any room-temperature ionic fluids which are hydrophilic and ionically conductive. The room-temperature ionic fluid may comprise one or more of a room-temperature ionic liquid and an ionic gel. Suitable examples include triethylsulfonium bis(trifluoromethylsulfonyl)imide ([SET3][TFSI]), 1-buthyl-3-methyl-imidazolium ([BMIM][CI]), and trioctylmethylammonium bis(trifluoromethylsulfonyl)imide ([OMA][TFSI]). The electrolyte 204 may further comprise one or more salts configured to aid the flow of protons from the first electrode 202 to the second electrode 203 and/or enhance the absorption of water by the room-temperature ionic fluid from the surrounding environment 205. The addition of the one or more salts therefore facilitates the generation and conduction of protons further thereby allowing even more electrical energy to be produced by the apparatus 201. Suitable salts include lithium bis(trifluoromethylsulfonyl)imide ([Li][TFSI]), lithium chloride and sodium chloride.
The present apparatus 201 has been found to exhibit a larger storage capacity and output voltage than existing proton batteries, and can be discharged at higher currents. This can be attributed at least partly to the presence of the room-temperature ionic fluid of the electrolyte 204. A number of experiments were performed to test the electrical properties of the apparatus 201. These experiments were performed using the configuration of
Once the room-temperature ionic fluid was applied to the apparatus 201, the open-circuit voltage increased from about 0.6V to about 1V, and the storage capacity increased from about 100 nAh (at a discharge current of 2 nA) to about 340 nAh (at a discharge current of 100 nA). The area of the GO/rGO junction 206 was then varied from ˜10 mm2 to ˜30 mm2 and then to ˜50 mm2 to determine how a larger active region would affect the electrical properties of the apparatus 201.
In an attempt to increase the output voltage of the apparatus, two devices were then connected in series to form a stack comprising two GO/rGO junctions with a junction area of ˜10 mm2. It was found that the open-circuit voltage was increased from 1V to 2.3V when the second cell/junction was added, and the storage capacity was increased from 340 nAh (at a discharge current of 100 nA) to 12 μAh (at a discharge current of 1 μA).
The electrical storage device 509 is configured to provide electrical power to the other components to enable their functionality. In this respect, the other components may be considered to be the external circuit referred to previously. The electronic display 512 is configured to display content stored on the apparatus 501 (e.g. stored on the storage medium 511), and the transceiver 513 is configured to transmit and/or receive data to/from one or more other devices via a wired or wireless connection.
The processor 510 is configured for general operation of the apparatus 501 by providing signalling to, and receiving signalling from, the other components to manage their operation. The storage medium 511 is configured to store computer code configured to perform, control or enable operation of the apparatus 501. The storage medium 511 may also be configured to store settings for the other components. The processor 510 may access the storage medium 511 to retrieve the component settings in order to manage the operation of the other components.
The processor 510 may be a microprocessor, including an Application Specific Integrated Circuit (ASIC). The storage medium 511 may be a temporary storage medium such as a volatile random access memory. On the other hand, the storage medium 511 may be a permanent storage medium such as a hard disk drive, a flash memory, or a non-volatile random access memory.
Other embodiments depicted in the figures have been provided with reference numerals that correspond to similar features of earlier described embodiments. For example, feature number 1 can also correspond to numbers 101, 201, 301 etc. These numbered features may appear in the figures but may not have been directly referred to within the description of these particular embodiments. These have still been provided in the figures to aid understanding of the further embodiments, particularly in relation to the features of similar earlier described embodiments.
It will be appreciated to the skilled reader that any mentioned apparatus/device and/or other features of particular mentioned apparatus/device may be provided by apparatus arranged such that they become configured to carry out the desired operations only when enabled, e.g. switched on, or the like. In such cases, they may not necessarily have the appropriate software loaded into the active memory in the non-enabled (e.g. switched off state) and only load the appropriate software in the enabled (e.g. on state). The apparatus may comprise hardware circuitry and/or firmware. The apparatus may comprise software loaded onto memory. Such software/computer programs may be recorded on the same memory/processor/functional units and/or on one or more memories/processors/functional units.
In some embodiments, a particular mentioned apparatus/device may be pre-programmed with the appropriate software to carry out desired operations, and wherein the appropriate software can be enabled for use by a user downloading a “key”, for example, to unlock/enable the software and its associated functionality. Advantages associated with such embodiments can include a reduced requirement to download data when further functionality is required for a device, and this can be useful in examples where a device is perceived to have sufficient capacity to store such pre-programmed software for functionality that may not be enabled by a user.
It will be appreciated that any mentioned apparatus/circuitry/elements/processor may have other functions in addition to the mentioned functions, and that these functions may be performed by the same apparatus/circuitry/elements/processor. One or more disclosed aspects may encompass the electronic distribution of associated computer programs and computer programs (which may be source/transport encoded) recorded on an appropriate carrier (e.g. memory, signal).
It will be appreciated that any “computer” described herein can comprise a collection of one or more individual processors/processing elements that may or may not be located on the same circuit board, or the same region/position of a circuit board or even the same device. In some embodiments one or more of any mentioned processors may be distributed over a plurality of devices. The same or different processor/processing elements may perform one or more functions described herein.
It will be appreciated that the term “signalling” may refer to one or more signals transmitted as a series of transmitted and/or received signals. The series of signals may comprise one, two, three, four or even more individual signal components or distinct signals to make up said signalling. Some or all of these individual signals may be transmitted/received simultaneously, in sequence, and/or such that they temporally overlap one another.
With reference to any discussion of any mentioned computer and/or processor and memory (e.g. including ROM, CD-ROM etc), these may comprise a computer processor, Application
Specific Integrated Circuit (ASIC), field-programmable gate array (FPGA), and/or other hardware components that have been programmed in such a way to carry out the inventive function.
The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole, in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that the disclosed aspects/embodiments may consist of any such individual feature or combination of features. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the disclosure.
While there have been shown and described and pointed out fundamental novel features as applied to different embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices and methods described may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. Furthermore, in the claims means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 14187884.3 | Oct 2014 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FI2015/050656 | 10/2/2015 | WO | 00 |
