Facile Access to CO2-Sourced Polythiocarbonate Dynamic Networks And Their Potential As Solid-State Electrolytes For Lithium Metal Batteries

Poly(monothiocarbonate)s are an interesting class of sulfur-containing materials whose application as solid polymer electrolytes was barely studied, certainly due to the elusive production of diversified polymer architectures. Herein, a new liquid CO2-sourced bis(alpha-alkylidene cyclic carbonate) monomer was designed at high yield to allow its one-step and solvent-free copolymerization with thiols to produce linear and cross-linked polymers in mild conditions. The influence of the monomer structure on the thermal properties and the ionic conductivity of linear polymers was assessed. The polymer network showed to be thermally re-processable owing to the dynamic nature of the monothiocarbonate bonds. A solid polymer electrolyte was easily obtained from the cross-linked material when combined with LiTFSI salt. The solid polymer electrolyte was characterized by an ionic conductivity reaching 6x10(-6) S cm(-1) at room temperature with a lithium transference number of 0.37 and a wide electrochemical stability window (4.0 V vs Li-0/Li+) valid for lithium cycling. This work thus reports an attractive valorizing approach for carbon dioxide to deliver under mild operating conditions poly(monothiocarbonate)-containing novel covalent adaptable network materials of high potential for energy applications, especially as solid electrolytes for batteries.

Automated summary

A new liquid CO2-sourced bis(alpha-alkylidene cyclic carbonate) monomer was successfully copolymerized with thiols to produce linear and cross-linked polymers. The thermal properties and ionic conductivity of the resulting linear polymers were studied. The cross-linked material combined with LiTFSI salt yielded a solid polymer electrolyte with high ionic conductivity and a wide electrochemical stability window, making it suitable for battery applications.