Tailoring Cathode Structure and Materials to Enable Fast Charging and Extended Lifespan in Li-S Batteries
Description
The practical implementation of Li–S batteries is limited by sluggish sulfur redox kinetics and inefficient ion transport in high-mass-loading cathodes, challenges that are further exacerbated under fast-charging and high-power operation. Conventional electrocatalyst-based strategies can partially suppress electrochemical polarization by lowering reaction energy barriers, yet they do not address concentration and ohmic polarizations, which dominate in thick electrodes. Here, we introduce a coupled material–architecture design that integrates electrocatalysts into a low-tortuosity, correlated dual-gradient electrode fabricated using programmable high-resolution stereolithography and pyrolysis-induced carbonization. By deliberately pairing a microscale pore-size gradient with a corresponding active-material gradient, the electrode synchronizes redox progression across its depth, ensuring more uniform sulfur utilization and mitigating concentration polarization. Pyrolysis further generates nanoscale porosity to create a hierarchical structure while converting polymer–salt precursors into a conductive carbon framework embedding Li₂S@Fe₂O₃/Fe–N–C. This architecture enhances ion accessibility, lowers ohmic polarization, and—through Fe₂O₃/Fe–N–C catalysis—accelerates polysulfide conversion, thereby reducing electrochemical polarization. Benefiting from this synergistic design, the Li₂S@Fe₂O₃/Fe–N–C dual-gradient electrode achieves high areal capacities of 22.7 mAh cm⁻² (1048 mAh g⁻¹) at 0.1 C and 15.7 mAh cm⁻² (725 mAh g⁻¹) at 5 C, while retaining 82% of its capacity over 1100 cycles at 4 C. A single-layer pouch cell delivers a specific energy of 403 Wh kg⁻¹, underscoring the potential of this dual-gradient strategy for practical high-energy, high-power Li–S battery systems.
Tailoring Cathode Structure and Materials to Enable Fast Charging and Extended Lifespan in Li-S Batteries
The practical implementation of Li–S batteries is limited by sluggish sulfur redox kinetics and inefficient ion transport in high-mass-loading cathodes, challenges that are further exacerbated under fast-charging and high-power operation. Conventional electrocatalyst-based strategies can partially suppress electrochemical polarization by lowering reaction energy barriers, yet they do not address concentration and ohmic polarizations, which dominate in thick electrodes. Here, we introduce a coupled material–architecture design that integrates electrocatalysts into a low-tortuosity, correlated dual-gradient electrode fabricated using programmable high-resolution stereolithography and pyrolysis-induced carbonization. By deliberately pairing a microscale pore-size gradient with a corresponding active-material gradient, the electrode synchronizes redox progression across its depth, ensuring more uniform sulfur utilization and mitigating concentration polarization. Pyrolysis further generates nanoscale porosity to create a hierarchical structure while converting polymer–salt precursors into a conductive carbon framework embedding Li₂S@Fe₂O₃/Fe–N–C. This architecture enhances ion accessibility, lowers ohmic polarization, and—through Fe₂O₃/Fe–N–C catalysis—accelerates polysulfide conversion, thereby reducing electrochemical polarization. Benefiting from this synergistic design, the Li₂S@Fe₂O₃/Fe–N–C dual-gradient electrode achieves high areal capacities of 22.7 mAh cm⁻² (1048 mAh g⁻¹) at 0.1 C and 15.7 mAh cm⁻² (725 mAh g⁻¹) at 5 C, while retaining 82% of its capacity over 1100 cycles at 4 C. A single-layer pouch cell delivers a specific energy of 403 Wh kg⁻¹, underscoring the potential of this dual-gradient strategy for practical high-energy, high-power Li–S battery systems.