All wet-coating process for chemical stable antimony and selenium dual-doped argyrodite electrolyte based all-solid-state lithium batteries

Abstract

Wet coating approach has been widely employed in the lithium ion battery industry due to well controlled thickness and scalability of electrodes, which is expected for sulfide electrolyte-based all-solid-state lithium batteries. The challenge lies in the chemical instability of sulfide electrolytes with air and solvents. Herein, Li_5.4PS_4.4Cl_1.6 with improved chemical/electrochemical stability and high room temperature ionic conductivity of 11.34 mS cm⁻¹ is realized by Sb₂Se₃ dual-doping. Benefiting from the formed SbS₄^3- units, the optimized Li_5.4P_0.95Sb_0.05S_4.325Se_0.075Cl_1.6 solid electrolyte possesses excellent air stability and ethyl acetate tolerance. The ionic conductivity of Li_5.4P_0.95Sb_0.05S_4.325Se_0.075Cl_1.6 after exposed in dry room for 12 h and humid air for 30 min is 9.42 and 1.73 mS cm⁻¹, much higher than those of Li_5.4PS_4.4Cl_1.6 with 6.51 mS cm⁻¹ and 0.52 mS cm⁻¹, respectively. Besides, the Li_5.4P_0.95Sb_0.05S_4.325Se_0.075Cl_1.6 also displays improved ionic conductivity retention of 72.7 % after soaked in ethyl acetate, resulting in an ultra-thin Li_5.4P_0.95Sb_0.05S_4.325Se_0.075Cl_1.6 membrane with thickness of 14 µm and high ionic conductivity of 2.19 mS cm⁻¹. Moreover, the Li_5.4P_0.95Sb_0.05S_4.325Se_0.075Cl_1.6 solid electrolyte delivers excellent interfacial compatibility against lithium metal with stable lithium plating/stripping for 6000 h at 0.1 mA cm⁻²/5 mAh cm⁻². The resultant LiNbO₃@LiCoO₂||Li all-solid-state lithium battery displays a high capacity retention of 81.9 % after 500 cycles at 1 C and the pouch cell with Li_5.4P_0.95Sb_0.05S_4.325Se_0.075Cl_1.6 membrane exhibits an initial discharge capacity of 118.7 mAh g⁻¹ with a capacity retention of 82.6 % after 500 cycles at 0.1 C.