A highly elastic polysiloxane-based polymer electrolyte for all-solid-state lithium metal batteries. Issue 19 (7th May 2021)

• Record Type: Journal Article
• Authors: Fu, Chengyin; Iacob, Mihail; Sheima, Yauhen; Battaglia, Corsin; Duchêne, Léo; Seidl, Lukas; Opris, Dorina M.; Remhof, Arndt
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 19(2021)
• Page Start: 11794
• Page End: 11801
• Publication Date: 2021-05-07
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d1ta02689e
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : An elastic electrolyte with a T g = −51 °C, an ionic conductivity of 4.8 × 10 −5 S cm −1, and a transference number of 0.53 showed a high initial capacity of 134 mA h g −1 and 75% capacity retention after 150 cycles at 0.1 mA cm −2 at 60 °C in a full cell. Abstract : Replacing the flammable liquid electrolyte currently used in most rechargeable lithium-ion batteries with a solid polymer electrolyte promises improved operational safety and increased energy density, e.g. by enabling lithium metal anodes. Polymer electrolytes typically suffer from low lithium-ion conductivity and limited electrochemical stability. We introduce a novel electrolyte based on a chemically cross-linked polysiloxane elastomer, modified with 3-mercaptopropiononitrile groups. The polysiloxane chains ensure high elasticity and low glass transition temperature, while the nitrile groups offer high dielectric permittivity and weak interaction with Li + . Combining these two properties into a solid polymer electrolyte results in excellent elasticity with no hysteresis after cyclic deformation, a low glass transition temperature (−51 °C), a high thermal stability up to at least 300 °C, an ionic conductivity of 4.8 × 10 −5 S cm −1 at 60 °C, and a high transference number of 0.53. In all-solid-state symmetric lithium cells, this electrolyte enables stable lithium plating and stripping at 0.1 mA cm −2 for over 1600 h at 60 °C. An all-solid-state full cell with a lithium iron phosphate cathode (areal capacity of 0.6 mA h cm −2 ) and lithium metal anode shows a high initial capacity of 134 mA h g −1 and 75% capacity retention after 150 cycles at 0.1 mA cm −2 at 60 °C. Preliminary results show that a room-temperature ionic conductivity as high as 6.4 × 10 −4 S cm −1 and stable lithium plating and stripping at 0.2 mA cm −2 for over 120 h at 22 °C can be achieved when the electrolyte is soaked in 1, 2-dimethoxyethane.