Regulating the non-effective carriers transport for high-performance lithium metal batteries

The absence of control over carriers transport during electrochemical cycling, accompanied by the deterioration of the solid electrolyte interphase (SEI) and the growth of lithium dendrites, has hindered the development of lithium metal batteries. Herein, a separator complexion consisting of polyacrylonitrile (PAN) nanofiber and MIL-101(Cr) particles prepared by electrospinning is proposed to bind the anions from the electrolyte utilizing abundant effective open metal sites in the MIL-101(Cr) particles to modulate the transport of non-effective carriers. The binding effect of the PANM separator promotes uniform lithium metal deposition and enhances the stability of the SEI layer and long cycling stability of ultra-high nickel layered oxide cathodes. Taking PANM as the Li || NCM96 separator enables high-voltage cycling stability, maintaining 72% capacity retention after 800 cycles at a charging and discharging rate of 0.2 C at a cut-off voltage of 4.5 V and 0 °C. Meanwhile, the excellent high-rate performance delivers a specific capacity of 156.3 mA h g−1 at 10 C. In addition, outstanding cycling performance is realized from −20 to 60 °C. The separator engineering facilitates the electrochemical performance of lithium metal batteries and enlightens a facile and promising strategy to develop fast charge/discharge over a wide range of temperatures.