Microspheres comprising Si/hollow Fe3O4/N-doped graphitic carbon via All-in-One beaker-spray assembly for dual-mechanism lithium storage

초록

Silicon is a promising anode material for next-generation lithium-ion batteries owing to its high theoretical capacity and low lithiation potential; however, its severe volume variation during cycling induces particle pulverization, interfacial instability, and persistent parasitic reactions. Herein, an All-in-One beaker-spray drying strategy is developed to construct carbon-integrated Si-based hybrid microspheres enabled by a sucrose-derived carbon glue (SCG) functioning as a multifunctional structural binder. The All-in-One beaker process forms silicon nanoparticles, hollow Fe3O4 nanostructures, and N-doped graphitic carbon (NGC) as integrated building blocks, while subsequent spray drying with SCG consolidates them into consolidated secondary microspheres. This consolidated architecture reduces electrolyte-accessible surface area and stabilizes the electrode framework. Within the SCG-integrated microspheres, the carbon glue immobilizes hybrid components and mitigates continuous SEI reconstruction. Hollow Fe3O4 accommodates silicon volume expansion and generates conductive metallic-Fe during conversion reactions, facilitating rapid charge-transfer kinetics, while the NGC ensures continuous electron transport. In-situ EIS/DRT analyses reveal activation-induced charge-transfer acceleration and suppressed interfacial resistance growth, confirming reversible evolution of characteristic relaxation processes within the consolidated architecture. Benefiting from these synergistic effects, the anode delivers a high rate capability (533 mA h g-1 at 5.0 A g-1 under constant current-constant voltage operation mode) and longterm stability over 800 cycles at 1.0 A g-1 and 1000 cycles at 3.0 A g-1. Full-cell evaluations paired with LiNi0.8Co0.1Mn0.1O2 confirm stable cycling performance. This work demonstrates a strategy for constructing structurally robust consolidated Si-based anodes with dual-mechanism lithium storage and validates their electrochemical feasibility under full-cell conditions.

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