US EPA

1256777 

Journal Article 

A nanostructured electrochromic supercapacitor 

Wei, D; Scherer, MR; Bower, C; Andrew, P; Ryhänen, T; Steiner, U 

2012 

1 

Nano Letters
ISSN: 1530-6984
EISSN: 1530-6992 

12 

4 

1857-1862 

English 

22390702 

10.1021/nl2042112 

WOS:000302524600020 

We report the first successful application of an ordered bicontinuous double-gyroid vanadium pentoxide network in an electrochromic supercapacitor. The freestanding vanadia network was fabricated by electrodeposition into a voided block copolymer template that had self-assembled into the double-gyroid morphology. The highly ordered structure with 11.0 nm wide struts and a high specific surface to bulk volume ratio of 161.4 μm(-1) is ideal for fast and efficient lithium ion intercalation/extraction and faradaic surface reactions, which are essential for high energy and high power density electrochemical energy storage devices. Supercapacitors made from such gyroid-structured vanadia electrodes exhibit a high specific capacitance of 155 F g(-1) and show a strong electrochromic color change from green/gray to yellow, indicating the capacitor's charge condition. The nanostructuring approach and utilizing an electrode material that has intrinsic electrochemical color-change properties are concepts that can be readily extended to other electrochromic intercalation compounds.