A family of oxychloride amorphous solid electrolytes for long-cycling all-solid-state lithium batteries

Abstract

Solid electrolyte is vital to ensure all-solid-state batteries with improved safety, long cyclability, and feasibility at different temperatures. Herein, we report a new family of amorphous solid electrolytes, xLi2O-MCly (M = Ta or Hf, 0.8 ≤ x ≤ 2, y = 5 or 4). xLi2O-MCly amorphous solid electrolytes can achieve desirable ionic conductivities up to 6.6 × 10−3 S cm−1 at 25 °C, which is one of the highest values among all the reported amorphous solid electrolytes and comparable to those of the popular crystalline ones. The mixed-anion structural models of xLi2O-MCly amorphous SEs are well established and correlated to the ionic conductivities. It is found that the oxygen-jointed anion networks with abundant terminal chlorines in xLi2O-MCly amorphous solid electrolytes play an important role for the fast Li-ion conduction. More importantly, all-solid-state batteries using the amorphous solid electrolytes show excellent electrochemical performance at both 25 °C and −10 °C. Long cycle life (more than 2400 times of charging and discharging) can be achieved for all-solid-state batteries using the xLi2O-TaCl5 amorphous solid electrolyte at 400 mA g−1, demonstrating vast application prospects of the oxychloride amorphous solid electrolytes.

Amorphous Chloride Solid Electrolytes with High Li-Ion Conductivity for Stable Cycling of All-Solid-State High-Nickel Cathodes

“…(b) Nyquist plots of the EIS measurement results of A-LTC and Bm_LiCl (inset) at 25 °C. (c) Arrhenius plot of ionic conductivities of the A-LTC together with those of crystalline sulfide, organic polymer, glassy oxide/sulfide, halide SEs, and LiPF 6 -based liquid electrolyte with the data adapted with permission from. ,,,,,,,− The A-LTC possesses a low activation energy and superionic conductivity close to that of the state-of-the-art sulfide SEs.…”

“…To compare the Li-ion conductivity of A-LTC with other SEs, we summarized Arrhenius plots of the ionic conductivity of the A-LTC together with typical polymer, glass-ceramic oxide/sulfide, ,,, halide, ,,, crystalline sulfide , SEs, and liquid electrolyte in Figure c. The Li-ion conductivities and activation energies are also summarized in Table S5.…”

“…The EIS of A-LTC displayed high bulk ionic conduction without the grain boundary (GB) resistance response (Figure 1b ) and interacted with LiCl to sharing common edges or corners within the amorphous matrix, which is different from other metal chlorides (ZrCl 4 , HfCl 4 , YCl 3 , InCl 3 , ScCl 3 and LaCl 3 ) with maintaining crystalline frameworks. [16][17][18]58,59 To compare the Li-ion conductivity of A-LTC with other SEs, we summarized Arrhenius plots of the ionic conductivity of the A-LTC together with typical polymer, 62 glass-ceramic oxide/sulfide, 28,29,60,61 halide, 41,42,44,63 crystalline sulfide 13,14 SEs, and liquid electrolyte 64 in Figure 1c. The Li-ion conductivities and activation energies are also summarized in Table S5.…”

“…32 Excellent electrochemical performance up to several thousand cycles has also been demonstrated for bulktype ASSLBs with crystalline halides in combination with bare high-voltage cathodes. [16][17][18]33,34 Recently, the ionic conductivity of the crystalline halide is further boosted by the modulation of the framework 35−37 and the formation of glass-ceramic phase 38−40 and glass phase, 41,42 indicating its potential in future application of practical ASSLBs. In addition, unique halide-eutectic and clay-like fluoride-halides 43,44 had been revealed with glass phase and excellent ionic conductivity.…”

“…Presently, ductile sulfide and oxysulfide-based amorphous SEs exhibit acceptable Li-ion conductivities (10 –4 –10 –3 S cm –1 ). , Unfortunately, it remains a great challenge to achieve high areal capacity and high voltage cathodes based on oxide, sulfide, or oxysulfide amorphous SEs due to the undesirable trade-off between ionic conductivity and cathode interfacial compatibility. ,, Aside from previously explored oxide SEs, chloride SEs have been recently proven to overcome the poor oxidative stability of sulfide SEs . Excellent electrochemical performance up to several thousand cycles has also been demonstrated for bulk-type ASSLBs with crystalline halides in combination with bare high-voltage cathodes. − ,, Recently, the ionic conductivity of the crystalline halide is further boosted by the modulation of the framework − and the formation of glass-ceramic phase − and glass phase, , indicating its potential in future application of practical ASSLBs. In addition, unique halide-eutectic and clay-like fluoride-halides , had been revealed with glass phase and excellent ionic conductivity.…”