Dramatic Enhancement Enabled by Introducing TiN into Bread-like Porous Si-Carbon Anodes for High-Performance and Safe Lithium Storage

Abstract

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