High-Strength Internal Cross-Linking Bacterial Cellulose-Network-Based Gel Polymer Electrolyte for Dendrite-Suppressing and High-Rate Lithium Batteries

Lithium is a promising anode material for high energy density batteries. However, the growth of lithium dendrite causes serious safety issues, which inhibits the application of lithium anode. Herein, a novel gel polymer electrolyte based on high-strength internal cross-linking bacterial cellulose network was prepared via an environmentally friendly and simple fast freeze-drying method. The as-obtained gel polymer electrolyte demonstrates an excellent lithium ion conductivity of 4.04 × 10^-3 S cm^-1 with an exceptional lithium ion transference number of 0.514 at 25 °C. The lithium metal battery with this gel polymer electrolyte shows an initial reversible capacity of 141.2 mA h g^-1 with a capacity retention of 104.2% (compared with the initial reversible capacity) after 150 cycles at 0.5 C. An average reversible capacity of 75.2 mA h g^-1 is maintained at high rate of 9 C. Moreover, this gel polymer electrolyte possesses superior mechanical strength of 49.9 MPa with a maximum strain of 56.33%. Therefore, the vertical growth of lithium dendrite is effectively suppressed. This research indicates the potential of applying low cost bacterial cellulose into high performance energy storage devices.