Ultrathin cobalt nickel selenides (Co0.5Ni0.5Se2) nanosheet arrays anchoring on Ti3C2 MXene for high-performance Na+/K+ batteries

Sodium-ion batteries (SIBs) have received increasing interest for large-scale energy storage based on the high natural abundance and low-cost of sodium resources. However, owing to the large ionic radius of sodium ion, SIBs anodes exhibit sluggish charge kinetic and rapid capacity decay, which severely hindered their practical application. In this work, we develop a novel approach to couple twodimensional (2D) bimetal Co-Ni selenide nanosheets with Ti3C2 MXene (Ti3C2/Co0.5Ni0.5Se2) as anode material for SIBs. Specifically, the 2D bimetal nanosheets anchoring on MXene substrate can provide high specific capacity and alleviate volume expansion. Furthermore, the MXene substrate can shorten the diffusion pathway of sodium-ion and enhance electronic conductivity. The Ti3C2/Co0.5Ni0.5Se2 delivers a superior rate performance of 337 mAh g-1 at 3000 mA g-1 and excellent stability of 338 mAh g-1 at 1000 mA g-1 after 600 cycles. The presented strategy from combination of MXene and 2D bimetallic selenide may pave a way for the design and synthesis of high-performance SIBs anode materials. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

Sodium-ion batteries have attracted attention for large-scale energy storage due to the abundance and low-cost of sodium resources. However, the sluggish charge kinetic and rapid capacity decay of SIB anodes caused by the large ionic radius of sodium ion have hindered their practical application. In this work, a novel approach is developed to combine two-dimensional bimetal Co-Ni selenide nanosheets with Ti3C2 MXene as anode material for SIBs, providing high specific capacity, alleviating volume expansion, shortening diffusion pathway, and enhancing electronic conductivity.