Synergistic lithium-ion transport in perovskite–halloysite nanotube composite solid electrolytes for high-performance lithium metal batteries

Safe and high-performance solid electrolytes—capable of fast ion transport and stable interfacial behavior—are essential for the commercialization of lithium metal batteries (LMBs). Herein, we present two types of LiTaO₃–halloysite nanotube (HNT) composite solid electrolytes—quasi-solid electrolyte (QSE) and dry solid electrolyte (DSE)—prepared using LiTaO₃ nanoparticles, HNT, and a poly(vinylidene fluoride) (PVDF) binder. The QSE exhibits high ionic conductivity (6.2 × 10⁻⁴ S cm⁻¹), a large Li⁺ transference number (0.74), and low activation energy (0.069 eV)—attributed to vacancy-hopping transport in LiTaO₃ and anion immobilization in HNT. Climbing-image nudged elastic band (CI-NEB) calculations further reveal complementary pathways—vacancy-hopping in LiTaO₃ and surface-assisted diffusion in HNT—supporting the experimentally observed high Li⁺ conductivity. Symmetric Li|Li cells with QSE demonstrate stable cycling for 1000 h without dendrite growth, while LiFePO₄|Li full cells deliver 159.5 mAh g⁻¹ at 0.2 C and retain 98.6% capacity after 200 cycles. In addition to QSE, DSE also exhibits good rate capability, long-term durability, and significant thermal stability up to 160 °C due to the synergistic contribution of LiTaO₃ and HNT. These findings demonstrate that LiTaO₃–HNT composite solid electrolytes are promising candidates for next-generation LMBs.