Three-dimensional structured nanoporous graphene/SnO2-based anode for high-power and high-energy-density lithium metal capacitors

초록

The demand for energy storage devices with both high power and energy density has risen significantly because of growing global environmental concerns. Lithium metal capacitors (LMCs) have emerged as promising candidates for next-generation energy storage systems by addressing the low energy density limitations of conventional electric double-layer capacitors (EDLCs). However, lithium dendrite formation and volume expansion in lithium metal anodes pose major challenges, leading to performance degradation and safety risks. In this study, a three-dimensional nano-perforated graphene (3-D NPG) with SnO2 composite as an advanced anode material for LMCs. The 3-D NPG improved electrochemical performance by offering a high surface area, reducing local current density, and mitigating volume expansion. Furthermore, the lithiophilicity of SnO2 facilitated lithium deposition by effectively reducing the lithium nucleation overpotential. The composite exhibited the lowest lithium nucleation overpotential (39.44 mV), along with a superior rate capability and remarkable cycle stability, retaining 88.5% of its capacity after 10,000 cycles at 2 A/g. The improved lithium-ion transport and lithiophilicity of the composite significantly suppressed dendritic lithium growth, thereby enhancing the electrochemical performance of LMCs. These results demonstrate the potential of 3-D SnO2/NPG as a next-generation anode material for high-performance energy storage applications.

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