Taming Active‐Ion Crosstalk by Targeted Ion Sifter Toward High‐Voltage Lithium Metal Batteries

Abstract Lithium metal batteries (LMBs), based on high‐voltage (HV) LiNi x Co y Mn z O 2 (NCM, x + y + z = 1) materials, exhibit great potential for next‐generation electric vehicle (EV) cells. Nevertheless, the inevitable dissolution and shuttle of transition metal (TM) ions from NCM cathodes poses a threat to the electrochemical sustainability of LMBs, especially at high voltage and high temperatures. Herein, ethylene diamine tetraacetic acid (EDTA)‐grafted MOF‐808 is proposed to serve as a multifunctional ion‐selective separator coating, in which EDTA molecules play a targeted ion sifter role in restricting active‐ion crosstalk. Judicious characterizations and theoretical calculations reveal that the separator coating effectively captures the TM‐ions in the electrolyte and thus ensures stable Li deposition without dendrites. As a result, the 4.5 V NCM622//Li cell with the ion‐selective separator achieves a high‐capacity retention over 1000 cycles with a high Coulombic efficiency of 99.68%, and its cycling stability at 55 °C is also upgraded. This crosstalk‐taming strategy offers fresh insight into constructing long‐life HV‐LMBs.