Ultrasound-induced elevation of interlayer spacing and conductivity of CoNi hydroxides for high-performance Ni–Zn batteries

Nickel–zinc (Ni–Zn) batteries hold a lot of promise for energy storage thanks to their high output voltage, plentiful Zn supply, and low toxicity. Achieving the facile preparation of high-performance cathodes at ambient temperature remains a challenge, it is however essential for practical applications. Here, in the present study, an efficient ultrasound-assisted one-step fabrication of CoNi double hydroxide (UA-CoNi DH) microspheres at room temperature that performs well as a cathode for Ni–Zn batteries was proposed. This designed ultrasound-assisted method induces the formation of metal double hydroxide with an elevation of interlayer spacing and bulk conductivity while maintaining the structure features of CoNi DH prepared without ultrasound assistance. As a result, the UA-CoNi DH as an electrode material displays highly enhanced electrochemical properties relative to CoNi DH prepared without ultrasound assistance. Benefitting from the improved performance of our UA-CoNi DH electrode, the Ni–Zn battery with UA-CoNi DH as the cathode (UA-CoNi DH//Zn) delivers a good specific capacity (202.36 mAh/g) and rate performance (70.49% capacity maintained at a 10-fold higher current), presenting more than 71.61% and 21.99% improvement relative to the CoNi DH//Zn battery, respectively. This work offers guidelines for constructing high-performance Ni–Zn battery cathodes in an open environment.