Interface-Structure-Modulated CuF₂/CF_x Composites for High-Performance Lithium Primary Batteries

Lithium primary batteries are widely used in various fields where high energy densities and long storage times are in demand. However, studies on lithium primary batteries are currently focused on the gravimetric energy densities of active materials and rarely account for the volumetric energy requirements of unmanned devices. Herein, CuF₂/CF_x composites are prepared via planetary ball milling (PBM) to improve the volumetric energy densities of lithium primary batteries using the high mass density of CuF₂, achieving a maximum volumetric energy density of 4163.40 Wh L⁻¹. The CuF₂/CF_x hybrid cathodes exhibit three distinct discharge plateaus rather than simple combinations of the discharge curves of their components. This phenomenon is caused by charge redistribution and lattice modulation on the contact surfaces of CuF₂ and CF_x during PBM, which change the valence state of Cu and modify the electronic structures of the composites. As a result, CuF₂/CF_x hybrid cathodes exhibit unique discharge behaviors and improved rate capabilities, delivering a maximum power density of 11.16 kW kg⁻¹ (25.56 kW L⁻¹). Therefore, it is a promising strategy to further improve the comprehensive performance of lithium primary batteries through the use of interfacial optimization among different fluoride cathodes.