Surface halogenation engineering for reversible silicon-based solid-state batteries.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41455732.
- Also identified by DOI 10.1038/s41467-025-67985-x and PMC identifier 12864858.
- Licence recorded as CC BY-NC-ND.
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Abstract
Silicon-based solid-state batteries are promising next-generation high-energy-density technologies. However, poor (electro)chemical compatibility between silicon negative electrodes and solid electrolytes (e.g., Li<sub>6</sub>PS<sub>5</sub>Cl) plus sluggish interfacial kinetics severely limits their reversibility and Coulombic efficiency. Here, we propose a surface halogenation strategy that transforms the native amorphous SiO<sub>2</sub> passivation layer on silicon particles into a functional Al(Si)OCl composite surface via controlled reaction with AlCl<sub>3</sub>. This artificial interphase reconciles interfacial incompatibility and enables fast ionic/electronic transport, suppressing irreversible lithium loss. The optimized negative electrode achieves a high initial Coulombic efficiency of 94.3% in half-cells and 85.6% initial Coulombic efficiency (86.6% with pre-lithiation) in full cells paired with LiNi<sub>0.88</sub>Co<sub>0.09</sub>Mn<sub>0.03</sub>O<sub>2</sub>. Enhanced reversibility further delivers long-term cyclability. The optimized negative electrode delivers 86% capacity retention and 99.998% average Coulombic efficiency over 200 cycles. Even at high-loading ( > 10 mAh cm<sup>-2</sup>, and no adhesives/conductive carbon/electrolyte), it retains 72% capacity after 500 cycles. The full cells maintain 80% capacity after 200 cycles at 1 C, with an average Coulombic efficiency exceeding 99.95%. The versatility of this halogenation strategy underscores halide chemistry's broad potential in advancing high-performance, reversible silicon-based solid-state batteries.