Dramatic Enhancement\nEnabled by Introducing TiN into\nBread-like Porous Si-Carbon Anodes for High-Performance and Safe Lithium\nStorage

Doping modifications and surface coatings are effective\nmethods\nto slow volume dilatation and boost the conductivity in silicon (Si)\nanodes for lithium-ion batteries (LIBs). Herein, using low-cost ferrosilicon\nfrom industrial production as the energy storage material, a bread-like\nnitrogen-doped carbon shell-coated porous Si embedded with the titanium\nnitride (TiN) nanoparticle composite (PSi/TiN@NC) was synthesized\nby simple ball milling, etching, and self-assembly growth processes.\nRemarkably, the porous Si structure formed by etching the FeSi<sub>2</sub> phase in ferrosilicon alloys can provide buffer space for\nsignificant volume expansion during lithiation. Highly conductive\nand stable TiN particles can act as stress absorption sites for Si\nand improve the electronic conductivity of the material. Furthermore,\nthe nitrogen-doped porous carbon shell further helps to sustain the\nstructural stability of the electrode material and boost the migration\nrate of Li-ions. Benefiting from its unique synergistic effect of\ncomponents, the PSi/TiN@NC anode exhibits a reversible discharge capacity\nup to 1324.2 mAh g<sup>–1</sup> with a capacity retention rate\nof 91.5% after 100 cycles at 0.5 A g<sup>–1</sup> (vs fourth\ndischarge). Simultaneously, the electrode also delivers good rate\nperformance and a stable discharge capacity of 923.6 mAh g<sup>–1</sup> over 300 cycles. This research can offer a potential economic strategy\nfor the development of high-performance and inexpensive Si-based anodes\nfor LIBs.