F and N Rich Solid Electrolyte for Stable All-Solid-State Battery

摘要

The instability of sulfide solid electrolytes to Li anode and high-voltage LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes limits the cyclic performance of all-solid-state lithium battery (ASSLB). Herein, the stability of Li6PS5Cl against Li anode is enhanced by mixing a small amount (0.32 wt) of CuF2-LiNO3 (CL) into Li6PS5Cl electrolyte layer to in-situ form a mixed-conductive-lithiophobic and self-healing LiF-Li3N-Cu solid electrolyte interphase (SEI) at Li6PS5Cl-CL/Li interface. The critical current density (CCD) of Li6PS5Cl-CuF2-LiNO3 increases to 1.4 mA cm(-2)/1.4 mAh cm(-2) at room temperature, which is much higher than that of pristine Li6PS5Cl (0.4 mA cm(-2)/0.4 mAh cm(-2)) even though mixing 0.32 wt CL into Li6PS5Cl slightly reduces the ionic conductivity from 2.9 x 10(-3) to 1.5 x 10(-3) S cm(-1). The compatibility of Li6PS5Cl-CL electrolyte to single-crystalline NMC811 (S-NMC811) is further enhanced by adding a small amount (0.02 wt) of AlF3 into Li6PS5Cl-CL forming Li6PS5Cl-CuF2-LiNO3-AlF3 (Li6PS5Cl-CLA) as a cathode electrolyte and by doing Cl- on S-NMC811 (Cl@S-NMC811) surface. The Cl@S-NMC811-Li6PS5Cl-CLALi6PS5Cl-CLLi cells with areal capacity of 2.55 mAh cm(-2) achieve a capacity retention of 69.4 after 100 cycles at 1C (1C = 200 mAh g(-1)). Adding a small amount of SEI and cathode/electrolyte interphase (CEI) former into the sulfide electrolytes with minimal reduction (48.3) of ionic conductivity is an effective method to enhance the performance of ASSLB.