Effect of Zn-substitution on cycling performance of α-Co(OH)2 nanosheet electrode for supercapacitors

Abstract

Interconnected α-Co(OH)₂ nanosheets with various proportions of substituted Zn were electrochemically deposited on nickel foam substrates. The architectures were used directly as electrodes for supercapacitors, which exhibited excellent pseudocapacitive performance. Compared with the pure α-Co(OH)₂ nanosheet electrode with a capacitance loss of 17.5% after 2000 cycles, the 9.7 at.% Zn-substituted α-Co(OH)₂ electrode showed stabilized capacitance with a loss of 1.1%, and the electrode with 21.1 at.% Zn substitution demonstrated a high cycling stability with a capacitance loss of only 0.6% from 652 F g⁻¹ after 2000 cycles. The enhanced cycling stability is attributed to the stabilization of the structure of the materials by the incorporation of inactive Zn²⁺ ions.