Intrinsic-Defect-Rich Hierarchical Porous Carbon Enabling Enhanced Power Generation in Sulfur-Based Thermally Regenerative Batteries

Thermally regenerative battery (TRB) systems as an emerging technology for converting low-grade waste heat into electricity show significant application potential but face challenges in terms of limited efficiency and cycling performance. To solve these problems, building upon a sulfur-based thermally regenerative battery (STRB), this work utilizes defect-rich hierarchically porous carbon architectures (DHPCs) as substrate materials for sulfur electrodes, investigating systematically the structural characteristics of sulfur electrodes based on nitrogen-doped hierarchically porous carbon architectures (NHPCs) and DHPCs, along with their effects on the power performance of STRBs. The results demonstrate polar defect sites in DHPCs effectively immobilize active materials, while the porous carbon walls facilitate rapid ion transport and promote chemical conversions. The STRB with DHPCs achieves a 77.78% increase in maximum power density, delivering high energy density (2.19 Wh L^-1) and capacity (1551.48 mAh g^-1); the STRB exhibits an excellent cycling stability (30 cycles, 80 h) with minimal capacity degradation. Moreover, density functional theory (DFT) calculations are performed to determine the adsorption and binding energies of intermediate CuS on various carbon surfaces. The results demonstrate that defect-rich carbon materials significantly enhance reactant adsorption and charge transfer, providing theoretical foundations for improving the battery power performance.