Sandwich composite PEO@(Er0.5Nb0.5)00.5Ti0.95O2@cellulose electrolyte with high cycling stability for all-solid-state lithium metal batteries

The development of solid electrolytes that have good mechanical stability, fast ion conductivity (Li+), high electrochemical stability, and low interfacial resistance is crucial for their use in all-solid-state lithium metal batteries (ASSLMBs). Herein, flexible composite polymer electrolytes (CPEs) composed of cellulose membrane sandwiched on both sides by polyethylene oxide/(Er0.5Nb0.5)(0.05)Ti0.95O2/lithium bis(trifluoromethylsulfonyl)imide (PEO/(Er0.5Nb0.5)(0.05)Ti0.95O2/LiTFSI, PENTLC) were fabricated and characterized. The cellulose membrane therein provides a mechanically strong skeleton that inhibits the growth of lithium dendrites, while (Er0.5Nb0.5)(0.05)Ti0.95O2 promotes the dissociation of lithium salt and ultimately improves the electrochemical performance of the CPEs due to the good dielectric constant of the ceramic. The PENTLC exhibits high ionic conductivity (6.66x10(-4) S cm(-1) at 60 degrees C) and a wide electrochemical window of up to 4.3 V (vs. Li/Li+). The Li=PENTLC=LiFePO4 delivers high discharge capacities (153.4 mAh g(-1) at 0.2 C and 129.2 mAh g(-1) at 1 C) and high cycling stability, with a capacity retention of 97.6% at 0.2 C after 100 cycles and 88.0% at 1 C after 200 cycles. These sandwich CPEs provide an effective strategy by which to achieve high-performance dendrite-free ASSLMBs that exhibit satisfactory cycling stability. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The flexible composite polymer electrolytes developed in this study, featuring cellulose membrane and ceramic composite materials, demonstrate high ionic conductivity, a wide electrochemical window, and the ability to inhibit the growth of lithium dendrites, leading to improved cycling stability of the batteries.