Chemical foaming integrated polydopamine hybridization towards high-performance cellulose-based separators for ultrastable and high-rate lithium metal batteries

High-performance cellulose-based separators are promising owing to biodegradation and electrolyte affinity. Nevertheless, strong hydrogen bonding interactions among cellulose nanofibers usually result in dense rather than porous membranes. Uncontrolled dendrite growth is also an obstacle for application of lithium metal anodes in the batteries. Herein, a novel strategy, i.e. chemical foaming integrated polydopamine hybridization, is developed to induce abundant pores and to improve electrolyte/lithium metal anode interfaces. The resultant cellulose-based separator has a high ionic conductivity of 0.81 mS/cm and can effectively suppress dendrite growth on lithium anodes. The coin cells, assembled by LiFePO4 cathode and lithium anode, behave superior cyclic stability at 5 C, and a high specific capacity of 130.7 m Ahg−1 is retained after 300 cycles. •Chemical foaming integrated polydopamine hybridization is developed.•The resultant cellulose separators have a high ionic conductivity.•Dendrite formation on lithium anodes are effectively suppressed.•The cells behave superior cyclic stability and rate capability.