Fabrication and characterization of Ni-based electrodes for improved NiZn battery performance

In this study, a hydrothermal method was used to synthesize nickel hydroxide (Ni(OH)2) powders, which are active materials for use in nickel (Ni) electrodes located in nickel-zinc (NiZn) batteries. X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta potential, Brunauer-Emmett-Teller (BET), and electrochemical characterization were used to characterize the cathode material in the prepared Ni electrodes. These results showed a β-phase Ni(OH)2 nanosphere with a well-crystalline structure. The electrochemical test results indicated the Ni electrode has a stable cyclic cycle in the half-cell. Based on the electrochemical performance results, the Ni electrode with Ni(OH)2, which was synthesized at 70oC for 3h of aging time (Ni_pH 12_3h_70oC), was the best-performing metal oxide. Compared with nickel electrodes, the NiCoZn electrode exhibited high OER (oxygen evolution reaction) and ORR (oxygen reduction reaction) activities because the combination of cobalt and zinc oxides with nickel provides excellent electrolyte access capability and promotes effective ion transfer through the active material. The NiZn battery with NiCoZn electrode showed a high capacity of 192.7 mAh gactive−1 at 10 mA cm−2 and cycling durability (after cycling at 10 mA cm−2 for 70 cycles). Benefiting from the excellent interaction between Ni, Co, and Zn, NiCoZn exhibited high onset potential and current density, suggesting that the NiCoZn electrode is a promising candidate as a high-performance configuration for Ni-based electrodes in NiZn batteries.