Advanced Porous SiOx/PAA Microarchitectures: A Sustainable Approach to High-Capacity and Ultra-Stable Anodes

Silicon suboxide (SiOx) anode materials are sought to substitute graphite-based anodes due to their high theoretical capacity and lower volume expansibility. Present chemical vapor deposition industrial production inevitably produces about 15 wt % submicro SiOx wastes. To improve the reuse of submicro SiOx wastes in a more economical, efficient, and sustainable way, present research focuses on exploring spherical porous SiOx/poly(acrylic acid) (PAA) microparticles via a spray-drying process to enhance resilience and adhesivity. The PAA polymer membrane uniformly coats the SiOx matrix via strong hydrogen bond interactions, providing mechanical strength to whole particles. The availability of polymer also possesses excellent electrochemical stability and adhesion, remaining almost free from pulverization during cycling. In half-cell testing, the synthesized micro SiOx/PAA particles demonstrate a higher initial capacity efficiency of 68% compared to that of submicro SiOx and a high reversible capacity of 1102 mAh g^-1 with a fading rate of 0.036% per cycle after 200 cycles at 2 A g^-1. Even after 1000 ultralong cycles, the capacity still remains above 200 mAh g^-1. The full-cell measurement shows a capacity of 160.25 mAh g^-1 for 600 cycles, suggesting their practicality for industrial production. Microsized SiOx anodes have shown impressive performance, achieving high Coulombic efficiency (>99.8%), exceptional rate capability, and outstanding cycling stability over 600 cycles.