Cellulose-Assisted Vertically Heterostructured PEO-Based Solid Electrolytes Mitigating Li-Succinonitrile Corrosion for Lithium Metal Batteries

Abstract

In the field of solid-state lithium metal batteries (SSLMBs), constructing vertically heterostructured poly(ethylene oxide) (PEO)-based solid electrolytes is an effective method to realize their tight contact with cathodes and Li anodes at the same time. Succinonitrile (SN) has been widely used in PEO-based solid electrolytes to improve the interface contact with cathodes, enhance the ionic conductivities, and obtain a high electrochemical stability window of PEO, but its application is still hindered by its intrinsic instability to Li anodes, which results in corrosion and side interactions with lithium metal. Herein, the cellulose membrane (CM) is introduced creatively into the vertically heterostructured PEO-based solid electrolytes to match the PEO-SN solid electrolytes at the cathode side. With the advantage of the interaction between −OH groups of CM and −C≡N groups in SN, the movement of free SN molecules from cathodes to Li anodes is limited effectively, resulting in a stable and durable SEI layer. In specific, the Li||LiFePO 4 battery with the CM-assisted vertically heterostructured PEO-based solid electrolyte by in situ preparation delivers a discharge capacity of around 130 mAh g −1 after 300 cycles and capacity retention of 95% after 500 cycles at 0.5 C. Our work provides a solution to construct PEO-based solid electrolytes feasible to match cathodes and Li anodes effectively by intimate contact with electrodes.

Enhanced lithium-ion conductivity and interficial stability of Li-IL@Fe-BDC composite polymer electrolytes for solid-state lithium metal batteries

“…This implies that these lithium-containing compounds form stable SEI films on the lithium metal surface, playing a crucial role in regulating the uniform deposition of lithium and inhibiting the growth of lithium dendrites. 26,53–55 The presence of Fe elements on the lithium metal surface is attributed to the incomplete removal of CPE3 during battery disassembly. The consistency of Fe elements on the lithium metal surface with those in CPE3 after cycling indicates the good electrochemical stability of Fe in the CPE3.…”

Three-Dimensional Metal–Organic Framework@Cellulose Skeleton-Reinforced Composite Polymer Electrolyte for All-Solid-State Lithium Metal Battery

“…The intensity of −CF 3 (688.5 eV) noticeably decreased, which can be attributed to the restriction of TFSI – (399.16 eV) movement by ZIF-67@CF during cycling. , In the N 1s spectra, as shown in Figure c,f,i, the components on the Li surface in LFP/PEO/Li and LFP/(ZIF-67@CF/PEO)/Li cells are consistent, indicating that ZIF-67@CF does not react with the anode. However, a small amount of Li 3 N (397.0 eV) appeared in the LFP/(ZIF-67@CF/PEO-SN)/Li cell, suggesting the occurrence of side reactions between SN and the Li anode, consistent with previous reports. ,, …”

Challenges and Solutions of Solid‐State Electrolyte Film for Large‐Scale Applications

“…The thickness of the obtained cathodesupported SSE was only 9.5 um (Figure 18A), and the Li|SSE|LFP batteries were prepared with an initial discharge capacity of up to 125 mA h g −1 at RT and 0.1 C. Capacity retention of up to 78% was achieved after 410 cycles of stable cycling. Tan et al [226] first cast the PEO-LiTFSI-SN-LLZTO (PL) precursor on the cathode surface using a scraper, and then introduced a cellulose membrane (CM) immediately on the PL layer. The PLCPB composite solid electrolyte with a total thickness of 59 um can be formed by casting the PEO-LiTFSI-BN (PB) precursor on the CM afterward (Figure 18B).…”

“…Reproduced with permission. [226] Copyright 2023, American Chemical Society. C) Optical and SEM images of LCO cathodes directly coated with LATP.…”

“…Compared with the solution casting method, the tape/slurry casting method has relatively complicated preparation steps, and the prepared SSE membranes have higher mechanical strength and ionic conductivity, with the significant advantage that special functional requirements can be met by layer-by-layer casting. [158] Four main designs including free-standing SSEs, [35,[209][210][211][212][213][214][215][216][217][218][219] skeleton or separator-supported SSEs, [220][221][222][223][224] cathode-supported SSEs, [225][226][227][228][229] and functional gradient SSEs [230,231] have been investigated in terms of structural design. However, the selection and content of solvents and binders in this method need to be carefully considered to avoid negative effects on ionic conductivity.…”