Biomimetic platinum forest enables 3D micro-supercapacitors with enhanced areal performance

Abstract

Nowadays, the rapid development of portable micro-electronics has stimulated a significantly increasing demand in micro-supercapacitors (MSCs) for efficient micropower sources. However, the performance of MSCs is hindered by the dense electrode design with sluggish ion diffusion or reaction kinetics and tortuous charge transfer pathways, especially at high mass loading. Inspired by the structure of natural forest with efficient solar energy utilization, we fabricate an innovative biomimetic Pt forest (named forest-like Pt) as a robust three-dimensional (3D) conductive current collector by a simple one-step electrodeposition process. This hierarchical nanoarchitecture significantly improves the exposed surface areas of active electrode materials. As a proof-of-concept, 3D MSCs based on poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymer grown on such forest-like Pt exhibit an enhanced areal capacitance of 69.3 mF cm−2 at 0.1 mA cm−2, which is more than 5-fold larger than that of pristine PEDOT-based MSCs using conventional flat Au current collectors. Furthermore, the assembled 3D MSCs show a high areal energy density (6.16 μW h cm−2) and outstanding rate capability (63.2 mF cm−2 even at 5 mA cm−2). Thus, this novel design concept provides a new approach to build advanced electrode nanoarchitectures for the next-generation MSCs.