Nanoporous Ni current collectors with cone array supported Sn–Co alloys as anodes for high-performance lithium-ion batteries

Abstract

Tin-based materials, characterized by their high specific capacities, show significant promise for use in the next generation of lithium-ion batteries (LIBs). However, the large volume change of Sn-based materials upon operation significantly compromises the battery performance. To solve this problem, a nanoporous Ni current collector with cone arrays is developed using a template-free method to support a Sn–Co alloy as an anode for LIBs. Interestingly, the Sn–Co alloy inherits the nanoporous cone array structure of the Ni current collector. Thus, the nanoporous and cone array-structured electrode provides abundant interspace to alleviate the mechanical stress of the Sn-based anode caused by volume changes and facilitate rapid mass transfer. Besides, the in situ generated inert Co dispersed in the electrode can further buffer the volume expansion of the Sn-based anode. Due to the synergistic effect, the electrode shows a high initial discharge/charge capacity of 1.34/0.64 mA h cm⁻² and a reversible capacity of 0.89 mA h cm⁻² with high coulombic efficiency (99.44%) even after 200 cycles at 1 mA cm⁻². Moreover, the electrode also demonstrates excellent rate performance (0.55 mA h cm⁻² at 8 mA cm⁻²). This work provides a novel design idea for the preparation of high-performance tin-based electrodes for next-generation lithium-ion batteries.