In-situ construction of high-mechanical-strength and fast-ion-conductivity interphase for anode-free Li battery

The solid electrolyte interphase(SEI)with strong mechanical strength and high ion conductivity is highly desired for Li metal batteries,especially for harsh anode-free batteries.Herein,we report a pragmatic approach to the in-situ construction of high-quality SEI by applying synergistic additives of Li NO_(3)and ethylene sulfite(ES)in the electrolyte.The obtained SEI exhibits a high average Young’s modulus(9.02GPa)and exchanging current density(4.59 mA cm^(-2)),which are 3.0 and 1.2 times as large as those using the sole additive of LiNO_(3),respectively.With this improved SEI,Li-dendrite growth and side reactions are effectively suppressed,leading to an ultra-high Coulombic efficiency(CE)of 99.7%for Li plating and stripping.When applying this improved electrolyte in full cells,it achieves a high capacity retention of 89.7%for over 150 cycles in a LiFePO_(4)||Li battery(~12 mg cm^(-2)cathode,50μm Li)and of 44.5%over 100 cycles in a LiFePO_(4)||Cu anode-free battery.