Passivating oxygen atoms in SiO through pre-treatment with Na2CO3 to increase its first cycle efficiency for lithium-ion batteries

Crystallographic Engineering in Micron-Sized SiOx Anode Material Toward Stable High-Energy-Density Lithium-Ion Batteries

The SiOx anode exhibits a high specific capacity and commendable durability for lithium-ion batteries (LIBs). However, its practical application is hindered by significant volumetric fluctuations during lithiation/delithiation, alongside a metastable nature, which induces mechanical instability and irreversible lithium consumption, ultimately impairing long-term capacity retention in full-battery cell configurations. In this study, we present a phase-engineering approach designed to improve the structural stability of SiOx anodes for LIB applications. By incorporating lithium fluoride, amorphous SiOx undergoes partial transformation into a quartz-like phase, which enhances mechanical integrity and mitigates irreversible lithium loss. This modified anode demonstrates significantly improved stability and prolonged cycle lifespan. Through a combination of multiscale simulations and in situ characterizations, we elucidate the stabilization mechanisms conferred by the quartz phase, providing critical insights into the role of SiOx's crystal structure in influencing degradation pathways. This work introduces an accessible and efficient method for controlling the crystallinity of SiOx, offering a practical solution to enhance the durability of high-energy-density LIBs.

Boosting the Cell Performance of the SiO/Cu and SiO/PPy Anodes via In-Situ Reduction/Oxidation Coating Strategies

Silicon monoxide (SiO) has attracted great attention due to its high theoretical specific capacity as an alternative material for conventional graphite anode, but its poor electrical conductivity and irreversible side reactions at the SiO/electrolyte interface seriously reduce its cycling stability. Here, to overcome the drawbacks, the dicharged SiO anode coated with Cu coating layer is elaborately designed by in-situ reduction method. Compared with the pristine SiO anode of lithium-ion battery (293 mAh g-1 at 0.5 A g-1 after 200 cycles), the obtained SiO/Cu composite presents superior cycling stability (1206 mAh g-1 at 0.5 A g-1 after 200 cycles). The tight combination of Cu particles and SiO significantly improves the conductivity of the composite, effectively inhibits the side-reaction between the active material and electrolyte. In addition, polypyrrole-coated SiO composites are further prepared by in-situ oxidation method, which delivers a high reversible specific capacity of 1311 mAh g-1 at 0.5 A g-1 after 200 cycles. The in-situ coating strategies in this work provide a new pathway for the development and practical application of high-performance silicon-based anode.