| abstract |
An apparatus comprising at least one substrate (722, 723), the at least one substrate (722, 723) comprising first (702) and second electrodes (703) and configured to form a sealed chamber with the first and second electrodes (702, 703) contained therein and facing one another, the sealed chamber comprising electrolyte (701) in the space between the first and second electrodes (702, 703), wherein the at least one substrate (722, 723) is configured to undergo reversible stretching whilst still forming the sealed chamber containing the electrolyte (701). |