Enabling high-performance solid-state batteries via a charge-heterogeneous dynamic interface effect by synergistic anion locking and cation transport

Solid-state batteries (SSBs) are pivotal for next-generation energy storage yet plagued by electrolyte-electrode interface dilemmas, including anion migration-triggered instability and sluggish Li⁺ transport. Herein, we propose an anion locking and cation transport synergistic strategy to achieve facilitated Li⁺ transport and stabilize the interface, thus addressing the core challenges of SSBs. Halloysite nanotubes with a negatively charged exterior and positively charged lumen are incorporated to architect a charge-heterogeneous dynamic interface within a cross-linked gel polymer electrolyte. The resulting dynamic interface concurrently immobilizes anions and facilitates salt dissociation, which collectively establish efficient Li⁺ transport highways, leading to enhanced ionic conductivity and stabilized electrode interfaces. This synergistic effect results in an exceptional ionic conductivity and a high Li⁺ transference number (0.64). Furthermore, the dynamic interface fosters the formation of a Li⁺-enriched interphase, which effectively suppresses lithium dendrite growth and enables outstanding high-voltage tolerance up to 4.7 V. Consequently, Li||LiFePO₄ cells deliver a long lifespan of 900 cycles with 94.7% of capacity retention at 1.0 C, and Li||Ni-rich full cells maintain high-capacity retention rate after 200 cycles. The practicality is further validated in a graphite||NCM523 pouch cell, which operates reliably under bending and cutting conditions. This work provides a groundbreaking design of dynamic interface engineering through charge heterogeneity, paving the way for developing safe, high-energy-density SSBs.