High-performance pseudocapacitive micro-supercapacitors with three-dimensional current collector of vertical ITO nanowire arrays

To meet the rapid development of miniaturized electronic devices, miniaturized power sources are highly demanded. Due to their high power density, longer lifetime and safety in use, microsupercapacitors (MSCs) are promising candidates for miniaturized energy storage devices. However, most of the reported MSCs possess a thin-film or paper-stacked structure, which exhibit a low areal or volumetric energy density. In order to improve the performance of MSCs to meet the demands of wider practical applications, the mass loading of active materials must be increased properly. Herein, we report an In2O3 : Sn (ITO) NWs three-dimensional (3D) network, which serves as the current collector and 3D scaffold for MSCs. After loading the active material (MnO2) and applying a facile and scalable laser-assisted fabrication strategy, the ITO NWs@MnO2 based in-plane interdigital MSC exhibited high areal capacitance of 193.8 mF cm−2. Moreover, it reveals a superior areal energy density of 26.94 μW h cm−2 with a peak areal power energy density of 15.07 mW cm−2 due to its highly conductive 3D network design and intimate contact between network and active material. To the best of our knowledge, this is the first time to introduce ITO NWs into MSCs. Therefore, this work offers a versatile ITO NWs 3D network into pseudocapacitive MSCs, which are promising miniaturized energy storage devices with high performance.