Abstract
Herein, we report a carbon-fiber-based freestanding electrode for NaVPO4F cathodes in sodium-ion batteries. The replacement of conventional aluminium foil with a carbon fiber mat-based current collector results in significant improvement in capacity at high rates and charge-discharge cycle stability. Petroleum-pitch (P-Pitch) has dual functions. P-pitch is used as a binder to bind NaVPO4F particles onto the carbon fiber mat, which helps to eliminate typical organic binders. At the same time, P-Pitch acts as a conducting precursor to coat onto NaVPO4F particles. The amount of P-pitch required to achieve stable electrochemical performance is optimized. As a result, 15 and 20% of P-pitch in the composite NaVPO4F electrodes (15P_NVPF@CF and 20P_NVPF@CF) shows stable electrochemical performances. A reversible capacity of 120 and 119 mAh g−1 is observed for 15P_NVPF@CF and 20P_NVPF@CF, with 97 and 98% retention in capacity after 300 cycles, respectively. Further, at a 0.5 C current rate, 15P_NVPF@CF and 20P_NVPF@CF electrodes show 86 and 87% capacity retention after 1000 cycles. The significant electrochemical performance of these freestanding electrodes is ascribed to the interlinked carbon matrix with NaVPO4F particles and carbon-fiber mat, which provides a continuous path for electronic conduction and faster kinetics of NaVPO4F particles.
Publisher
The Electrochemical Society
Subject
Materials Chemistry,Electrochemistry,Surfaces, Coatings and Films,Condensed Matter Physics,Renewable Energy, Sustainability and the Environment,Electronic, Optical and Magnetic Materials
Cited by
5 articles.
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