Layer stacked SiO_x microparticle with disconnected interstices enables stable interphase and particle integrity for lithium-ion batteries

Severe mechanical fracture and unstable interphase, associated with the large volumetric expansion/contraction, significantly hinder the application of high-capacity SiO_x materials in lithium-ion batteries. Herein, we report the design and facile synthesis of a layer stacked SiO_x microparticle (LS-SiO_x) material, which presents a stacking structure of SiO_x layers with abundant disconnected interstices. This LS-SiO_x microparticle can effectively accommodate the volume expansion, while ensuring negligible particle expansion. More importantly, the interstices within SiO_x microparticle are disconnected from each other, which efficiently prevent the electrolyte from infiltration into the interior, achieving stable electrode/electrolyte interface. Accordingly, the LS-SiO_x material without any coating delivers ultrahigh average Coulombic efficiency, outstanding cycling stability, and full-cell applicability. Only 6 cycles can attain >99.92% Coulombic efficiency and the capacity retention at 0.05 A g⁻¹ for 100 cycles exceeds 99%. After 800 cycles at 1 A g−1, the thickness swelling of LS-SiO_x electrode is as low as 0.87%. Moreover, the full cell with pure LS-SiO_x anode exhibits capacity retention of 91.2% after 300 cycles at 0.2 C. This work provides a novel concept and effective approach to rationally design silicon-based and other electrode materials with huge volume variation for electrochemical energy storage applications.