Ion-regulating Hybrid Electrolyte Interface for Long-life and Low N/P Ratio Lithium Metal Batteries

•A robust cellulose-based composite gel electrolyte (r-CCE) capable of stabilizing ion deposition is reported via compositing bacterial cellulose skeleton with Li6.4La3Zr1.4Ta0.6O12 particles.•r-CCE not only achieves high ionic conductivity (1.68 × 10−3 S/cm) with a remarkable Li-ion transfer number (∼0.92) and a wide window of electrochemical stability (∼5.3 V), but also helps stabilize the Li anode.•Utilizing ultrathin lithium metal anodes (15 μm), ultra-stable symmetric Li/Li cells that are armed with r-CCE demonstrate a highly stable plating/stripping process.•A high areal capacity of ∼4.2 mAh/cm2, and 100 cycles with obviously improved stability of the full Li metal batteries with n/p ratio of ∼0.74 is achieved.