Boosting the electrochemical performance of LiFePO4 cathodes via direct growth of carbon nanotube networks

초록

Olivine-structured LiFePO4 (LFP) is a promising cathode material for lithium-ion batteries (LIBs) due to its high thermal stability and structural robustness. However, its intrinsically low electrical conductivity and moderate energy density require conductive modification to achieve high-rate capability. Carbon nanotubes (CNTs) are particularly attractive owing to their excellent electrical conductivity and mechanical resilience, which provide efficient electron transport pathways during charge-discharge processes. In this study, we synthesize CNTs directly on LFP surface (CNT@LFP composites) using a rotary chemical vapor deposition system and employ them as cathode materials in LIBs. Electrodes are fabricated via a dry process with a polytetrafluoroethylene binder, and the impact of CNTs on electrochemical performance of LIBs is systematically investigated. The optimized CNT@LFP composite exhibits higher capacity, improved cycling stability, superior rate capability, and the lowest charge-transfer resistance compared with commercial carbon-coated LFP/C, highlighting the role of interconnected CNT networks in enhancing electronic conductivity. Importantly, the electrochemical performance exhibits a clear dependence on CNT loading, indicating that an optimal CNT content is required to achieve the best balance between electrical conductivity and electrochemical stability. These results demonstrate that direct CNT growth on LFP is a promising approach to maximize the performance of LFP cathodes in advanced LIBs.

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