Pseudo single lithium-ion conductors enabled by a metal–organic framework with biomimetic lithium-ion chains for lithium metal batteries

Abstract

The development of new and efficient, non-precious metal-based single lithium-ion conductors is one of the premier challenges in lithium metal batteries (LMBs). Inspired by the biologic proton chains, we designed pseudo single lithium-ion conductors (PSLICs) by immobilizing liquid electrolytes in a unique Zr-carboxylate framework. Such unique PSLIC contains biomimetic lithium ion chains and exhibits high lithium ionic conductivity (0.35 mS cm⁻¹) and low activation energy (0.19 eV). As illustrated by density functional theory calculations, single lithium ion chains can be formed within PSLIC, and lithium ions can be transported by jumping between solvents and anions. LiFePO₄|Li cell with such PSLIC exhibits significantly extended cycling life (>900 cycles) with 77% capacity retention and improved Coulombic efficiency (>97%).