Promoting OH- Adsorption and Diffusion Enables Ultrahigh Capacity and Rate Capability of Nickel Sulfide Cathode for Aqueous Alkaline Zn-Based Batteries

Aqueous alkaline Zn-based batteries (AAZBs) possess great promise for large-scale applications thanks to their higher discharging plateau and unique reaction mechanism. However, the capacity and rate capability of Ni-based cathodes are still unsatisfactory due to their insufficient OH- adsorption and diffusion ability. Herein, heterostructured Ni3S2/Ni(OH)(2) nanosheets with outstanding electrochemical performance are synthesized via a facile chemical etching strategy. The heterostructured Ni3S2/Ni(OH)(2) nanosheet cathode shows significantly increased capacity and rate capability due to its boosted OH- adsorption and diffusion ability compared to Ni3S2. Consequently, the assembled Zn//Ni3S2/Ni(OH)(2) cell can deliver an ultrahigh capacity of 2.26 mAh cm(-2), an excellent rate performance (0.91 mAh cm(-2) at 100 mA cm(-2)) and a satisfying cycling stability (1.01 mAh cm(-2) at 20 mA cm(-2) after 500 cycles). Moreover, a prominent energy density of 3.86 mWh cm(-2) is obtained, which exceeds the majority of recently reported AAZBs. This work is expected to provide a new modification direction for developing high-performance nickel sulfide cathode for AAZBs.

Automated summary

Heterostructured Ni3S2/Ni(OH)2 nanosheets with excellent electrochemical performance were synthesized using a facile chemical etching strategy. Compared to Ni3S2, the heterostructured nanosheet cathode showed improved OH- adsorption and diffusion ability, resulting in increased capacity and rate capability. The assembled battery demonstrated high capacity, excellent rate performance, and cycling stability, with a prominent energy density.