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Buffering volume change in solid-state battery composite cathodes with CO2-derived block polycarbonate ethers

DOI: 10.1021/jacs.2c06138 DOI Help

Authors: Georgina L. Gregory (University of Oxford) , Hui Gao (University of Oxford) , Boyang Liu (University of Oxford) , Xiangwen Gao (University of Oxford) , Gregory J. Rees (University of Oxford) , Mauro Pasta (University of Oxford) , Peter G. Bruce (University of Oxford) , Charlotte K. Williams (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of The American Chemical Society

State: Published (Approved)
Published: September 2022
Diamond Proposal Number(s): 29810

Open Access Open Access

Abstract: Polymers designed with a specific combination of electrochemical, mechanical, and chemical properties could help overcome challenges limiting practical all-solid-state batteries for high-performance next-generation energy storage devices. In composite cathodes, comprising active cathode material, inorganic solid electrolyte, and carbon, battery longevity is limited by active particle volume changes occurring on charge/discharge. To overcome this, impractical high pressures are applied to maintain interfacial contact. Herein, block polymers designed to address these issues combine ionic conductivity, electrochemical stability, and suitable elastomeric mechanical properties, including adhesion. The block polymers have “hard-soft-hard”, ABA, block structures, where the soft “B” block is poly(ethylene oxide) (PEO), known to promote ionic conductivity, and the hard “A” block is a CO2-derived polycarbonate, poly(4-vinyl cyclohexene oxide carbonate), which provides mechanical rigidity and enhances oxidative stability. ABA block polymers featuring controllable PEO and polycarbonate lengths are straightforwardly prepared using hydroxyl telechelic PEO as a macroinitiator for CO2/epoxide ring-opening copolymerization and a well-controlled Mg(II)Co(II) catalyst. The influence of block polymer composition upon electrochemical and mechanical properties is investigated, with phosphonic acid functionalities being installed in the polycarbonate domains for adhesive properties. Three lead polymer materials are identified; these materials show an ambient ionic conductivity of 10 –4 S cm–1, lithium-ion transport (tLi+ 0.3–0.62), oxidative stability (>4 V vs Li+/Li), and elastomeric or plastomer properties (G′ 0.1–67 MPa). The best block polymers are used in composite cathodes with LiNi0.8Mn0.1Co0.1O2 active material and Li6PS5Cl solid electrolyte–the resulting solid-state batteries demonstrate greater capacity retention than equivalent cells featuring no polymer or commercial polyelectrolytes.

Journal Keywords: Electrodes; Electrolytes; Ionic conductivity; Polymers; Thermoresponsive polymers

Diamond Keywords: Batteries; Solid-State Batteries (SSB)

Subject Areas: Materials, Chemistry, Energy


Instruments: DL-SAXS-Offline SAXS and Sample Environment Development

Added On: 24/09/2022 17:05

Documents:
jacs.2c06138.pdf

Discipline Tags:

Energy Storage Energy Physical Chemistry Energy Materials Chemistry Materials Science Polymer Science

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS)