Cold sintering of a Li-ion cathode: LiFePO₄-composite with high volumetric capacity

Cold Sintering Process (CSP) is a new emerging technique to consolidate ceramic particulates and ceramic-based composites at ultralow temperatures with assistance of pressures and transient aqueous phases. In consideration of the low-temperature advantage that bridges the sintering conditions of different types of materials (e.g. ceramics and polymers), it thus opens up a new route to integrate materials and devices, as well as to enable the fabrication of novel composites particularly with the ceramic material as matrix. In this communication, we demonstrated the feasibility of applying CSP to achieve dense LiFePO₄-based cathode composites at an extraordinary low-temperature ~240 °C. The cold-sintered composite cathodes exhibited ~89% of its theoretical density. A half-cell was subsequently assembled, and a good electrochemical performance was manifested by a high volumetric capacity ~340 mAh/cm³ and a gravimetric capacity ~158 mAh/g. Furthermore a good rate performance and capacity retention during cycling test at 0.2 C was observed on these composites.