Binder-Induced Interfacial Engineering of a Dual-Layered SEI for Durable Silicon Anodes Over a Wide Temperature Range

Silicon is a promising next-generation anode for high-energy-density lithium-ion batteries, yet its practical application is hindered by severe volume variation, structural degradation, and unstable solid-electrolyte interphase (SEI). Herein, a novel multifunctional binder PNTA, composed of polyacrylic acid and nitrilotriacetic acid, is designed to enhance both the structural and interfacial stability of silicon anodes. The robust hydrogen-bonding network of PNTA preserves structure integrity of the electrode during cycling. Meanwhile, the binder strongly impacts the electrode-electrolyte interfacial properties by tuning local microenvironment (EC, DEC, and PF₆⁻ concentration), facilitating Li⁺ desolvation and regulating preferential reduction, thus inducing a unique dual-layer SEI enriched with N-containing and LiF components. This SEI demonstrates exceptional stability, combining energy-dissipative characteristics with rapid Li⁺ conduction, which ensures long-term cyclability and wide-temperature operation. As envisioned, the Si@PNTA anode exhibits outstanding cycling stability (>984 mAh g⁻¹ after 1000 cycles at 2 A g⁻¹) and superb performance from −15°C to 120°C. Moreover, this novel binder is well adapted to high-loading SiO_x and Si/C anodes, achieving areal capacities of 4.98 and 3.74 mAh cm⁻², respectively. By exploring the fundamental mechanisms of interfacial tailoring, this work offers a new pathway to promote the overall properties of silicon-based anodes via innovative multifunctional binders.