In-situ synthesis of Si@G@TiC double protective layer structure for enhancing cycling stability of lithium-ion batteries

Si-based materials are considered as the highly promising candidates for the next-generation high performance Li-ion batteries, and the development of Si/graphite anode is regarded as one of the common approaches to realize commercial application of it. Unfortunately, although the introduced graphite phase improves the electrical conductivity, the poor interfacial bonding strength as well as the limited ability to relieve the volume expansion of silicon still lead to the inferior cycle performance. Herein, a novel Si-based anode structure is constructed and modified with a double protective layer, in which the inner graphite is in close contact with silicon to improve the electrical conductivity while partially alleviating the volume expansion of silicon, and the outer rigid TiC layer further stabilizes the electrode structure as well as suppress the side reactions between active materials and electrolyte. Owing to the unique structural design, the cycling performance of the Si@G@TiC electrode is greatly improved, and the capacity retention of the electrode is high up to 85% after 300 cycles at 0.2 A g−1.