Bidirectionally Compatible Buffering Layer Enables Highly Stable and Conductive Interface for 4.5 V Sulfide‐Based All‐Solid‐State Lithium Batteries

Abstract

High‐voltage all‐solid‐state lithium batteries (HVASSLBs) are considered attractive systems for portable electronics and electric vehicles, due to their theoretically high energy density and safety. However, realization of HVASSLBs with sulfide solid electrolytes (SEs) is hindered by their limited electrochemical stability, resulting in sluggish interphase dynamics. Here, a bidirectionally compatible buffering layer design scheme is proposed to overcome the interfacial challenges of sulfide‐based HVASSLBs. As a proof of concept, it is found that NASICON‐type LixZr2(PO4)3 surprisingly exhibit great compatibility with both 4.5 V LiCoO2 and Li6PS5Cl, based on the results of first‐principles calculations and various in situ/ex situ characterizations. This compatibility significantly restrains the interface reactivity and boosts interfacial Li‐ion transport. Therefore, 4.5 V sulfide‐based HVASSLBs can exhibit remarkably enhanced initial discharge capacity (143.3 vs 125.9 mAh·g−1 at 0.2C), capacity retention (95.53% vs 74.74% after 100 cycles), and rate performance (97 vs 45 mAh·g−1 at 2C). This work sheds light on the great prospects of sulfide‐based HVASSLBs with high‐rate characteristics, and constitutes a crucial step toward the rational design of interface and interphase chemistry for high‐performance sulfide‐based HVASSLBs.

Solid Electrolyte with Oxidation Tolerance Provides a High‐Capacity Li2S‐Based Positive Electrode for All‐Solid‐State Li/S Batteries

“…In coating materials for high voltage active materials, even though the oxidation voltage of coating materials (Li 2 CO 3 , [ 68 ] Li 3 BO 3 , [ 68 ] LiNbO 3 , [ 20 ] Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 , [ 69 ] Li 2 ZrO 3 , [ 20 ] and LiZr 2 (PO 4 ) 3 [ 70 ] ) is lower than the cut off voltage of ASSBs with high voltage active materials, the coating materials have significantly decreased the interfacial resistance. [ 71–75 ] Therefore, those coating materials would be also oxidized on the high voltage active materials but they still work as the Li ion conductive material. Based on the study about coating materials for high voltage electrode and the obtained Nyquist plots (Figure 3b), we speculate that the oxidation of LiI was limited and the interface area between Li 2 S and LiI would be maintained (Figure 3e).…”

Multiscale understanding of high-energy cathodes in solid-state batteries: from atomic scale to macroscopic scale

“…However, there is one thing in common for all cathode materials that no electrode can escape the effect of surface/interface structure evolution at the atomic scale during battery cycling. In SSBs, it has been reported that many transition metals (TMs) at a high oxidation state have been found to be unstable against SEs [61][62][63]. The instability of surface phase and side reactions at CAM-SE interface could cause severe structure evolution, resulting in fast capacity fading.…”

Highly reversible Li2RuO3 cathodes in sulfide-based all solid-state lithium batteries

“…, Li 2 WO 4 –LCO/Li 6 PS 5 Cl, LiZr 2 (PO 4 ) 3 –LCO/Li 6 PS 5 Cl, LiNbO 3 –NCM811/Li 10 SnP 2 S 12 , etc. , 32–34 but most are limited to less than 180 mA h g −1 due to the material's own capacity limitation. Therefore, it is appealing to apply high-capacity lithium-rich cathode materials in ASSLBs to improve their practical energy density.…”