One-body style photo-supercapacitors based on Ni(OH)2/TiO2 heterojunction array: High specific capacitance and ultra-fast charge/discharge response

Abstract

In this work, a type of “one-body” photo-supercapacitors (PSs) with high specific capacitance and ultrafast response of charge/discharge is constructed, in which TiO 2 plays a role of photoelectric conversion material and Ni(OH) 2 serves as the energy storage material. The results show that the discharge specific capacitance of 22.9 mF/cm 2 and the charge and discharge response time of 40 and 30 ms in this type of PSs is prior to that in previous works. The large discharge specific capacitance and ultrafast response mainly attribute to the direct storage and release of charges in loose Ni(OH) 2 structure. This study provides a simple fabrication process of PSs with high performance for the direct storage of solar energy and offers reference for the application of other materials in PSs. • The morphology of Ni(OH) 2 on TiO 2 nanorod arrays could be regulated precisely. • TiO 2 nanorod arrays loaded with flower-like Ni(OH) 2 showed p-n junction effect. • Photo charge and dark discharge can be performed by the same working electrode. • The PSs showed ultrafast response, high specific capacitance and stability.