Selenium-regulated band structure engineering in CF cathodes enables high-power and wide-temperature Li/CF primary batteries.

Li/CF primary batteries are renowned for their exceptional energy density, yet their practical deployment is hindered by the inherently sluggish kinetics of the CF cathode. This study addresses this limitation by incorporating selenium (Se) into CF (denoted as CF/Se) via a facile low-temperature thermal treatment, significantly enhancing its electrochemical performance. Comprehensive spectroscopic and electrochemical analyses reveal that Se doping induces the formation of CSe bonds, which promote semi-ionic CF bonding, thereby accelerating Li diffusion and reducing charge transfer resistance. Density functional theory calculations further demonstrate that Se doping modulates the electronic structure of CF, narrowing its bandgap to establish an efficient conductive network and markedly improving electronic conductivity. The optimized CF/Se-1 composite (Se:CF = 1:9) delivers outstanding performance, achieving a discharge capacity of 383.9 mAh g at a high current density of 20 A g with an energy density of 765.7 Wh kg and a power density of 3.99 × 10 W kg. Moreover, CF/Se-1 exhibits remarkable wide-temperature operability (-35 to 60 °C), retaining a capacity of 485.3 mAh g at 0.5 A g with a stable 2.0 V plateau even at -35 °C. This work underscores the pivotal role of Se doping in tailoring the band structure of CF, unlocking its potential for high-power and extreme-temperature Li/CF batteries.