Preparation and Electrochemical Performance of NiCo2O4 and Its Composite Material as Cathode Material for Aqueous Zinc-Ion Batteries

Abstract

Lithium-ion batteries are the most widely used in commercial applications. However, the scarcity of resources and high price seriously restrict the development of lithium-ion batteries. The aqueous zinc-ion batteries have higher ionic conductivity, environmental stability, safety and high storage of zinc. The present study demonstrates a novel material of aqueous zinc-ion batteries by which NiCo2O4/CNT material was prepared by solvothermal method + calcination method. At the current density of 100 mA·g−1, the specific discharge capacity of NiCo2O4/CNT positive electrode is 99.2 mAh·g−1 for the first time, and 57.8 mAh·g−1 after 300 cycles, while only 5.6 mAh·g−1 remains in the positive electrode of NiCo2O4. This is due to the excellent conductivity of CNT, improve the conductivity of the composite material. It also increases the specific surface area of the material. The active sites of Zn2+ adsorption/desorption were increased, and the specific capacitance of the material was also increased. The volume change of electrode material caused by electrode reaction is inhibited, and the stability of the material is improved. This study highlights that the combination of NiCo2O4 material and multiwalled carbon nanotube improves the performance of aqueous zinc-ion batteries, which can guide the future design of stream zinc-ion batteries.