Tree-Trunk Design for Flexible Quasi-Solid-State Electrolytes with Hierarchical Ion-Channels Enabling Ultralong-Life Lithium-Metal Batteries

The construction of robust (quasi)-solid-state electrolyte (SSE) for flexible lithium-metal batteries is desirable but extremely challenging. Herein, a novel, flexible, and robust quasi-solid-state electrolyte (QSSE) with a tree-trunk design is reported for ultralong-life lithium-metal batteries (LMBs). An in-situ-grown metal-organic framework (MOF) layer covers the cellulose-based framework to form hierarchical ion-channels, enabling rapid ionic transfer kinetics and excellent durability. A conductivity of 1.36 x 10(-3) S cm(-1), a transference number of 0.72, an electrochemical window of 5.26 V, and a good rate performance are achieved. The flexible LMBs fabricated with as-designed QSSEs deliver areal capacity of up to 3.1 mAh cm(-2) at the initial cycle with high mass loading of 14.8 mg cm(-2) in Li-NCM811 cells and can retain approximate to 80% capacity retention after 300 cycles. An ultralong-life of 3000 cycles (6000 h) is also achieved in Li-LiFePO4 cells. This work presents a promising route in constructing a flexible QSSE toward ultralong-life LMBs, and also provides a design rationale for material and structure development in the area of energy storage and conversion.

Automated summary

This study reports a novel tree-trunk design flexible and robust quasi-solid-state electrolyte for ultralong-life lithium-metal batteries. The electrolyte forms hierarchical ion-channels, enabling rapid ion transfer kinetics and excellent durability. Flexible batteries fabricated with this electrolyte achieve high capacity and excellent cycle life under high load and mass loading.