Conducting network interface modulated rate performance in LiFePO4/C cathode materials

Abstract

Carbon can play a critical role in electrode, especially for LiFePO4 cathode, not only serving as continuous conducting network for electron pathway, but also boosting Li+ diffusion through providing sufficient electrons. Here, we report the modulation of electrode/electrolyte interface to yield excellent rate performance by creating cross-linked conducting carbon network in LiFePO4/C cathode material. Such conducting networks inhibit agglomeration and growth of LiFePO4/C primary particles and hence lead to a short Li+ diffusion pathway. Furthermore, it also offers fast electron transmission rate and efficient electron for Li storage in the LiFePO4 sheath. The LiFePO4/C with carbon nanotubes (CNTs) delivers a discharge capacity of 150.9 mAh·g−1 at 0.1C (initial Coulombic efficiency of 96.4%) and an enhanced rate capability (97.2 mAh·g−1 at 20.0C). Importantly, it exhibits a high cycle stability with a capacity retention of 90.3% even after 800 cycles at 5.0C (0.85 A·g−1). This proposed interface design can be applied to a variety of battery electrodes that face challenges in electrical contact and ion transport. Graphical abstract: [Figure not available: see fulltext.]