Abstract
Sulfide solid-state electrolytes (SSEs) are promising candidates for next-generation high-safety all-solid-state lithium batteries (ASSLBs). However, they still face challenges such as low anodic stability limits and poor interfacial compatibility with high-voltage cathode active materials. Here, we present a series of fluorine-doped argyrodite sulfide SSEs, Li(5.5)PS(4.5)Cl(1.5-x)F(x) (LPSCl(1.5-x)F(x)) (0 < x ≤ 1.5), toward high-voltage LiCoO(2) (LCO)-based ASSLBs, via the in situ formation of a stable fluorine-containing passivating interphase on the cathode active materials surface. Notably, fluorine incorporation significantly raises the practical oxidation limit of LPSCl(1.5) from 2.4 to 3.5 V for LPSClF(0.5), while maintaining a high room-temperature ionic conductivity of 3.3 mS cm(-1). This enhancement is attributed to increased lithium-ion disorder and fluorine's high electronegativity. The ASSLBs, fabricated by directly assembling an LPSClF(0.5) SSE with an uncoated commercial LCO cathode, demonstrate stable cycling with low polarization voltage at 4.3 V (vs. Li(+)/Li), achieving 92.1% capacity retention after 700 cycles at 0.2 C. Remarkably, even under a 4.6 V high-voltage condition, our battery maintains 96.2% capacity retention over 300 cycles, attributed to the in situ formation of a stable fluorine-containing cathode-electrolyte interphase on the LCO surface. When coupled with a lithium metal anode, Li|LPSClF(0.5)|LCO ASSLB achieved stable cycling at 4.6 V and delivered 137 mAh g(-1) after 100 cycles at 0.5 C. Significantly, the Si|LPSCl(1.5)|LPSClF(0.5)|LCO ASSLB, cycled at an ultra-high mass loading LCO of 203.8 mg cm(-2), exhibits an exceptional areal capacity of 25.7 mAh cm(-2), demonstrating immense potential of LPSClF(0.5) SSE for practical high-energy ASSLBs.