Effect of copper doping on NiCo₂O₄ nanostructures as anode material for enhanced electrochemical performance of lithium-ion batteries

Abstract

The surging demand for high-energy density lithium-ion batteries (LIBs) necessitates the exploration of anode materials with higher storage capacity. Nickel‑cobalt (Ni-Co) based transition metal oxides (TMOs) are strong contenders due to their high theoretical capacity based on conversion reactions. The copper (Cu) doping strategy is adopted to improve the electrochemical performance through addressing the drawbacks of NiCo₂O_4, such as lower conductivity and volume expansion. In this work, Cu-doped NiCo₂O₄ nanomaterials are synthesized via a rapid, efficient, and scalable microwave-assisted synthesis route. When evaluated as an anode material for LIBs, the Cu-doped NiCo₂O₄ electrode delivers a high reversible specific capacity of 662 mAh g⁻¹ at a current density of 100 mAg⁻¹. The enhanced performance is attributed to the unique porous nanorod-like structure with a high surface area of 59.4 m²/g, which provides short lithium-ion diffusion pathways. Significantly, the copper acts as an inactive material that accommodates volume changes effectively during cycling when compared to pure NiCo₂O₄. Furthermore, the electrode exhibits an excellent rate capability and remarkable cycling stability. These findings indicate that copper doping is found to be an efficient approach for enhancing the cyclic performance of TMO-based anodes for next-generation LIBs.