High rate and ultralong life flexible all-solid-state zinc ion battery based on electron density modulated NiCo2O4 nanosheets

The development of zinc ion batteries (ZIBs) with large capacity, high rate, and durable cathode material is a crucial and urgent task. NiCo2O4 (NCO) has received ever-growing interest as a potential cathode material for ZIBs, owing to the high theoretical capacity, rich source, cost-effective, and versatile redox nature. However, due to the slow dynamics of the NCO electrodes, its practical application in high-performance systems is severely limited. Herein, we report an electron density modulated NCO nanosheets (N-NCO NSs) with high-kinetics Zn2+-storage capability as an additive-free cathode for flexible all-solid-state (ASS) ZIBs. By virtue of the enhanced electronic conductivity, improved reaction kinetics, and increased active sites, the optimized N-NCO NSs electrode delivers a high capacity of 357.7 mAh g(-1) at 1.0 A g(-1) and a superior rate capacity of 201.4 mAh g(-1) at 20 A g(-1). More importantly, a flexible ASS ZIBs device is manufactured using a solid polymer electrolyte of a poly (vinylidene fluoride hexafluoro-propylene) (PVDF-HFP) film. The flexible ASS ZIBs device shows superb durability with 80.2% capacity retention after 20,000 cycles and works well in the range of -20-70 degrees C. Furthermore, the flexible ASS ZIBs achieves an impressive energy density as high as 578.1 W h kg(-1) with a peak power density of 33.6 kW kg(-1), substantially outperforming those latest ZIBs. This work could provide valuable insights for constructing high-kinetics and high-capability cathodes with long-term stability for flexible ASS ZIBs. (C) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

NiCo2O4 as a potential cathode material for zinc ion batteries has high theoretical capacity and rich source, but its practical application is limited due to slow electrode dynamics.