Catalytic Tin Nanodotsin Hard Carbon Structures forEnhanced Volumetric and Power Density Batteries

The demand for fast-charging and high-energy-density energy storage systems necessitates advanced anode materials with enhanced performance. This study introduces hard carbon-encaged tin (Sn) nanodots (HCSN) as a versatile composite anode for lithium-ion and sodium-ion batteries, designed to address the present challenges. HCSN is synthesized via a sol–gel process and controlled thermal reduction; subsequently, the HCSN700 electrode features uniformly distributed Sn nanodots within a robust hard carbon matrix, effectively mitigating volume expansion and enhancing structural stability. The structure enables fast-charging capabilities through improved electrochemical kinetics and delivers a high volumetric energy density in full cells. In lithium-ion batteries, HCSN700 achieves stable cycling performance and gradual capacity increases driven by catalytic Sn nanodots facilitating reversible Sn–O bond formation. In sodium-ion batteries, the electrode demonstrates reliable long-term operation, leveraging the synergy between hard carbon and nanosized Sn. This work underscores the potential of HCSN700 for high power and volumetric energy density applications in next-generation energy storage systems.