3D nanoporous Cu-Ni column arrays with integrated NiS/CuS composites as anode for lithium-ion batteries: A reinforced buffer structure for high-performance electrodes

Conversion-type transition metal sulfides (TMSs) demonstrate tremendous potential as anode materials for lithium-ion batteries (LIBs) due to their high capacities (>500mAh g⁻¹) and favorable physicochemical properties. However, their practical application of TMSs anode is constrained by sluggish ions/electron transfer dynamics and electrode disintegration from volume expansion. Herein, 3D nanoporous NiS/CuS composites (NiS/CuS@CNCA) derived from copper-nickel column arrays (CNCA) and anchored on nickel foam substrates, are engineered as a high-speed conductive network and stress-buffering scaffold for TMSs anode through template-free galvanostatic electrodeposition and followed by in-situ sulfurization. The optimal NiS/CuS@CNCA-5 electrode, prepared with a 5-hour vulcanization, delivers an initial capacity of 0.91mAh cm⁻² at 0.4 mA cm⁻² and maintains a stable reversible capacity of 0.77 mAh cm⁻² after 150 cycles, with an excellent rate capability of 0.57 mAh cm⁻² at 3.2 mA cm⁻². Elastic bending of thin-plated model tests demonstrates that the hierarchical porous array structure of NiS/CuS@CNCA-5 effectively mitigates stress caused by volume expansion during repeated cycles. Such an integrated nanoporous columnar-array-structured framework, specifically tailored to accommodate active materials, establishes a foundational strategy to address volume expansion issues that plague other electrodes.