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

Lithium metal batteries (LMBs), based on high-voltage (HV) LiNixCoyMnzO2 (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 degrees C is also upgraded. This crosstalk-taming strategy offers fresh insight into constructing long-life HV-LMBs. A multifunctional ion-selective separator is strategically designed for tackling the chronic issue of active-ion crosstalk. The synergetic interactions of the separator accurately capture active ions while ensuring a homogenized lithium-ion flux, which results in smooth lithium growth and rollover-free cycling stability.image