Chem
Volume 7, Issue 11, 11 November 2021, Pages 3052-3068
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Article
In situ formation of polymer-inorganic solid-electrolyte interphase for stable polymeric solid-state lithium-metal batteries

https://doi.org/10.1016/j.chempr.2021.06.019Get rights and content
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Highlights

  • Thin composite polymer electrolyte enables Li-metal batteries with Co-free LiNiO2

  • No formation of dead Li with a Li plating/stripping efficiency of >99%

  • LiF-SEI and salt-rich interlayer suppress the formation of Li dendrites and dead Li

  • Highly reversible LiNiO2 Li-metal battery with a retention of 81% after 200 cycles

The bigger picture

Next-generation rechargeable batteries, consisting of Li anode, solid-state electrolytes, and Ni-rich cathodes, are desired to meet future energy-storage needs with high energy density, low cost, and safety. Developing composite polymer electrolytes (CPEs) is one of the right directions for achieving this goal. Extensive research has been devoted to exploring polymeric Li-metal batteries, but only limited progress has been made because of unstable interfaces and unconstrained Li-dendrite growth. Herein, we designed a thin salt-concentrated interlayer on CPEs via simple UV polymerization for stabilizing Li anode and Co-free LiNiO2 cathode to achieve excellent cycling stability (81% retention after 200 cycles), rate performance, and high average Coulombic efficiency of >99.5%. This work provides a reliable method to make CPEs suitable for high-energy Li-metal batteries and thus paves the way to commercialization of quasi-solid- or solid-state lithium batteries.

Summary

Composite polymer electrolytes (CPEs) for solid-state Li-metal batteries (SSLBs) still suffer from gradually increased interface resistance and unconstrained Li-dendrite growth. Herein, we addressed the challenges by designing a LiF-rich inorganic solid-electrolyte interphase (SEI) through introducing a fluoride-salt-concentrated interlayer on CPE film. The rigid but flexible CPE helps accommodate the volume change of electrodes, while the polymeric highly concentrated electrolyte (PHCE) surface-layer regulates Li-ion flux due to the formation of a stable LiF-rich SEI via anion reduction. The designed CPE-PHCE presents enhanced ionic conductivity and high oxidation stability of >5.0 V (versus Li/Li+). Furthermore, it dramatically reduces the interfacial resistance and achieves a high critical current density of 4.5 mA cm−2. The SSLBs, fabricated with thin CPE-PHCE membranes (<100 μm) and Co-free LiNiO2 cathodes, exhibit exceptional electrochemical performance and long cycling stability. This approach of SEI design can also be applied to other types of batteries.

Keywords

interfacial chemistry
composite polymer electrolyte
lithium dendrite
solid-electrolyte interphase
lithium batteries

UN Sustainable Development Goals

SDG7: Affordable and clean energy
SDG9: Industry innovation and infrastructure
SDG11: Sustainable cities and communities

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4

These authors contributed equally

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