Apparatus and Associated Methods for Electrical Storage

#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.

#A description is now given, by way of example only, with reference to the accompanying drawings, in which:

#FIG. 1a illustrates an existing proton battery in plan view;

#FIG. 1b illustrates the proton battery of FIG. 1a in cross-section;

#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).

#FIGS. 1a and 1b show an existing graphene oxide-based proton battery 101 in plan view and cross-section, respectively. The battery 101 comprises a first electrode 102 formed from graphene oxide and a second electrode 103 formed from reduced graphene oxide.

#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.