ScholarWorks@중앙대학교

초록

Potassium–selenium (K–Se) batteries are regarded as promising next-generation energy-storage systems due to their high theoretical energy density and the natural abundance of potassium resources. Nevertheless, at high selenium loadings, the intrinsically low conductivity of selenium and its significant volume expansion during repeated cycling severely limit practical utilization and long-term stability. To address these issues, we propose a hierarchically porous carbon host specifically designed to accommodate high selenium contents while simultaneously mitigating structural degradation and enhancing electronic pathways. Hierarchically porous flower-shaped carbon spheres (HP-FCSs) were fabricated via KOH activation, followed by the incorporation of 70 wt% selenium. The HP-FCS framework integrates interconnected micropores and mesopores with a defect-enriched graphitic network, which collectively ensure uniform selenium dispersion, strong confinement, accelerated ion/electron transport, and efficient buffering of volume changes. Consequently, the Se70@HP-FCS electrode achieves a reversible capacity of 156.5 mA h g−1 after 500 cycles at 0.5C with 68.1% retention, and delivers 184.8 mA h g−1 at 3.0C. These results highlight the crucial role of hierarchical porosity and surface defect engineering in enabling both high selenium loading and prolonged cycling stability, providing valuable insights into the rational design of advanced electrode architectures for potassium–selenium batteries.

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