Ultrathin composite polymer electrolyte with ordered ion pathways for all-solid-state lithium-metal batteries

Abstract

Thin yet robust solid-state electrolytes (SSEs) with efficient Li⁺ transport are highly desirable for realizing high-energy-density all-solid-state lithium-metal batteries (ASSLMBs). Herein, an ultrathin (10 μm) SSE with ordered ion pathways is reported for scalable ASSLMBs production. The SSE is supported by the poly (ether sulfone) scaffold, which not only improves mechanical strength and safety capability but also enables low-tortuous Li⁺ transport along the inner walls of its vertically aligned microchannels. The fast and direct Li⁺ conduction facilitates uniform Li deposition and the scaffold-reinforced structure provides superior dendrite suppression capability, together enhancing interfacial stability with the Li metal anode. As a result, the composite electrolyte exhibits room temperature ionic conductivity up to 0.10 mS cm⁻¹ and Li⁺ transference number up to 0.51. Moreover, the LiFePO₄/Li ASSLMBs achieve capacity retention of 81 % after 300 cycles at 1 C/60 °C and 84 % after 100 cycles at 0.1 C/room temperature. Notably, the cell is able to operate safely and exhibit excellent electrochemical performance under high temperature of 100 °C. The versatility of the strategy is illustrated by a demonstration of the LiNi_0.8Co_0.1Mn_0.1O₂ system.