Li-Rich Antiperovskite/Nitrile Butadiene Rubber Composite Electrolyte for Sheet-Type Solid-State Lithium Metal Battery

Abstract

Lithium-rich antiperovskites (LiRAPs) hold great promise to be the choice of solid-state electrolytes (SSEs) owing to their high ionic conductivity, low activation energy, and low cost. However, processing sheet-type solid-state Li metal batteries (SSLiB) with LiRAPs remains challenging due to the lack of robust techniques for battery processing. Herein, we propose a scalable slurry-based procedure to prepare a flexible composite electrolyte (CPE), in which LiRAP (e.g., Li2OHCl0.5Br0.5, LOCB) and nitrile butadiene rubber (NBR) serve as an active filler and as a polymer scaffold, respectively. The low-polar solvent helps to stabilize the LiRAP phase during slurry processing. It is found that the addition of LOCB into the NBR polymer enhances the Li ion conductivity for 2.3 times at 60°C and reduces the activation energy (max. 0.07 eV). The as-prepared LOCB/NBR CPE film exhibits an improved critical current of 0.4 mA cm−2 and can stably cycle for over 1000 h at 0.04 mA cm−2 under 60°C. In the SSLiB with the sheet-type configuration of LiFePO4(LFP)||LOCB/NBR CPE||Li, LFP exhibits a capacity of 137 mAh/g under 60 at 0.1°C. This work delivers an effective strategy for fabrication of LiRAP-based CPE film, advancing the LiRAP-family SSEs toward practical applications.

Revisiting the Role of Hydrogen in Lithium‐Rich Antiperovskite Solid Electrolytes: New Insight in Lithium Ion and Hydrogen Dynamics

“…It is reported that the mass loss during the high‐temperature solid reaction is less than 1%. [ 33 ] Therefore, it is easy to tune the H amount in the LiRAPs by replacing a part of LiOH with Li 2 O. O–H vibration mode features a shoulder peak positioned at 3660 cm −1 in FTIR spectrum, [ 17 ] as shown in Figure 1c. As the H amount decreases, the intensity of the shoulder peak is gradually weakened.…”

“…By replacing the flammable liquid electrolyte with nonflammable solid electrolytes (SEs), all‐solid‐state Li metal batteries (ASSLMBs) are considered as safer alternatives for energy storage compared with the commercial Li‐ion batteries. [ 1–13 ] Among the reported families of SEs, Li‐rich antiperovskite (LiRAP) SEs (e.g., Li 3 OCl) possess the advantages of high Li ion conductivity (10 −3 S cm −1 ), low activation energy (<0.3 eV), wide electrochemical window, light weight, low cost, and low toxicity, [ 14–21 ] which show great promises for practical applications. They have a similar crystal structure to the conventional perovskites but with electronically inverted lattice sites.…”

“…However, compared with Li 3 OX, Li 2 OH X exhibit smaller ionic conductivity and larger activation energy. [ 15,17,31–32 ] A fundamental question to these phenomena is the elusive role of H, whose rotational motion is intimately correlated to Li migration. Song et al.…”

“…However, compared with Li 3 OX, Li 2 OHX exhibit smaller ionic conductivity and larger activation energy. [15,17,[31][32] A fundamental question to these phenomena is the elusive role of H, whose rotational motion is intimately correlated to Li migration. Song et al suggested that the rotation of -OH group in Li 2 OHCl facilitated the nearby Li ion transport according to the molecular dynamics calculations.…”

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storage compared with the commercial Li-ion batteries. [1][2][3][4][5][6][7][8][9][10][11][12][13] Among the reported families of SEs, Li-rich antiperovskite (LiRAP) SEs (e.g., Li 3 OCl) possess the advantages of high Li ion conductivity (10 −3 S cm −1 ), low activation energy (<0.3 eV), wide electrochemical window, light weight, low cost, and low toxicity, [14][15][16][17][18][19][20][21] which show great promises for practical applications. They have a similar crystal structure to the conventional perovskites but with electronically inverted lattice sites.

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