Unveiling the Advantages of Silicon Nitride Nanoparticle Anodes for Enhanced Cyclic Stability, Rate Performance, and Mechanical Robustness.

Silicon nitride, known as a convertible-type silicon-based anode material, has emerged as a promising alternative to pure Si anodes, featuring improved cyclic stability, rate performance, and kinetics. This study reports on the electrochemical properties of silicon nitride nanoparticles as an anode material. It demonstrates that this anode outperforms a pure silicon anode in terms of cyclic stability and kinetics. Silicon nitride undergoes conversion during initial lithiation, forming a matrix phase that facilitates charge carrier transport that enhances performance. As a result, silicon nitride retains 73% of its initial charge capacity, whereas only 55% for pure silicon, after 350 cycles. The in situ-formed ion-conductive matrix promotes Li-ion transport, yielding an improved rate performance. At 1 C rate, silicon nitride achieves 585 mA h g (38% of C/20 capacity) after 85 cycles, surpassing pure silicon's 470 mA h g (22% of C/20 capacity). Electrochemical impedance indicates silicon nitride's faster ionic conductivity and lower resistance compared to pure silicon. Electrochemical dilatometer findings show less electrode thickness increase in silicon nitride (29%) than in pure silicon (60%) during initial lithiation. Silicon nitride demonstrates potential as an attractive anode material for future Li-ion batteries due to improved cyclic stability, superior rate performance, and stable electrode geometry.