Abstract
Nickel (oxy)hydroxides are widely used as cathode materials in alkaline rechargeable batteries, including NiOOH-Cd, NiOOH-Zn and Ni-metal hydride batteries. NiOOH is a 2D-layered compound, known to exist in three different polymorphs α, β and γ. Compared with β-NiOOH, γ-NiOOH has a higher theoretical specific capacity and a lower self-discharge rate. However, when using a battery-grade Ni(OH)2, the β-NiOOH is mainly formed, which may transform to γ-NiOOH in the long run. Batteries based on β-NiOOH have poor life cycling and suffer from volume expansion. Therefore, γ-NiOOH is a desirable electrode material which can also be used in the next-generation high-capacity metal-air batteries due to its excellent electrocatalytic activity towards oxygen evolution reaction (OER).In this presentation, we will report a new synthesis method of γ-NiOOH, in which only γ-phase is formed. The method is based on in-situ electrochemical transformation of a two-dimensional nickel chelate polymer in a carbon matrix in an alkaline electrolyte. γ-NiOOH prepared in this way is highly crystalline and has an excellent catalytic activity towards OER with overpotential of 390 mV at 12 mA/cm2. In addition, it can also catalyze oxygen reduction reaction (ORR), with an onset potential of 0.81 V vs. RHE in 1 M KOH.AcknowledgementsThe authors would like to thank Japan Society for Promotion of Science under the JSPS KAKENHI Grant Number JP 20K05689 for financial supports.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
