Core-shell transition metal disulfide grafted carbon matrix composite as an anode material for high-performance lithium-ion batteries

Abstract

Lithium-ion batteries are essential for powering a wide range of applications, from portable electronics to electric vehicles. As demand grows for high-capacity and long-lasting batteries, the development of advanced anode materials has become critical. Transition metal disulfides (TMDs) have emerged as promising candidates due to their layered structures and high theoretical capacities. This study introduces a cobalt disulfide (CoS₂) and carbon composite with a core-shell structure as a TMD-based anode material engineered to enhance lithium-ion battery performance. The composite's architecture, consisting of CoS₂ nanoparticles embedded within carbon hollow spheres, promotes high electrical conductivity, efficient ion transport, and stability against volume changes during cycling. Detailed structural and compositional analysis confirms the robust integrity of the composite. Electrochemical tests demonstrate an initial discharge capacity of approximately 1000 mAh g⁻¹, stabilizing at 850 mAh g⁻¹ in subsequent cycles with minimal voltage polarization. The composite retains a capacity of 300 mAh g⁻¹ after 400 cycles and achieves nearly 100 % Coulombic efficiency, reflecting excellent reversibility. It also exhibits superior rate capability, maintaining 300 mAh g⁻¹ at a high current density of 3 A g⁻¹, with full capacity recovery upon returning to lower rates. The carbon hollow spheres enhance conductivity and buffer against expansion, while the CoS₂ nanoparticles improve electron transport and electrochemical kinetics. This study underscores the potential of TMD-based core-shell composites, as high-performance anode materials, advancing the development of next-generation lithium-ion batteries with enhanced efficiency, durability, and reliability.