Melamine-formaldehyde resin-derived carbon and graphene synergistically coated porous silicon for high-performance lithium-ion battery anodes

Abstract

Silicon-based anode materials have garnered significant attention as a leading candidate for next-generation batteries, primarily attributed to their remarkable theoretical capacity (4200 mAh g^-1), low operating potential (0.4 V vs Li/Li⁺), and naturally abundant resource characteristics. However, the practical implementation of silicon anodes encounters substantial obstacles stemming from insufficient electrical conductivity, severe volumetric expansion during charge/discharge cycles, and instability within the solid-electrolyte interphase (SEI) formation. To address these issues, this paper synthesizes melamine formaldehyde resin via a two-step liquid-phase method and encapsulates porous silicon with graphene in combination. After pyrolysis, a PSi@MFC/rGO composite anode material with nitrogen-doped carbon coating and graphene as the conductive matrix was synthesized, exhibiting excellent electrochemical performance. The 0.4PSi@MFC/rGO-0.009 composite anode material synthesized with moderate silicon content (0.4 g) and graphene loading (9 ‰) exhibited the optimal performance. The material displayed an initial discharge capacity of 2574.9 mAh g^-1 within the first three charge-discharge cycles under an activation current density of 0.1 A g^-1. Subsequently, it achieved a reversible capacity of 881.1 mAh g^-1 after 200 cycles at 0.5 A g^-1. Even following 400 continuous cycles at 1 A g^-1, the composite retained a substantial reversible capacity of 625.3 mAh g^-1 while preserving excellent cycling stability. This study presents a facile, cost-effective, and viable processing strategy for fabricating silicon anodes.