A 2D–3D co-conduction effect in PEO-based all-solid-state batteries for long term cycle stability. Issue 14 (6th April 2021)

• Record Type: Journal Article
• Authors: He, Hao; Chai, Yuan; Zhang, Xinlong; Shi, Penghui; Fan, Jinchen; Xu, Qunjie; Min, Yulin
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 14(2021)
• Page Start: 9214
• Page End: 9227
• Publication Date: 2021-04-06
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0ta10523f
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : We synthesized a lithium ion conductor oxide, Li19 La36 Ga7 O74, with high bulk conductivity and used it as an active filler to improve the long-cycle stability and low self-discharge of PEO-based lithium metal solid-state batteries. Abstract : The insufficient ionic conductivity and serious interface problems of oxide-based solid electrolytes greatly limit the performance of all solid-state lithium rechargeable batteries. Herein, a new type of lithium-ion conductor oxide Li19 La36 Ga7 O74 (LLGO) with a high bulk conductivity of 1.4 × 10 −3 S cm −1 which is higher than that of Li7 La3 Zr2 O12 (LLZO, 7 × 10 −4 S cm −1 ) is synthesized to solve the poor ionic conductivity problem. Based on density functional theory (DFT), LLGO has a two-dimensional and three-dimensional (2D–3D) co-conduction lithium ion migration path. Using LLGO as a conductor filler, the polyethylene oxide (PEO)/LiTFSI/LLGO (PLG) composite prepared by solution casting served as solid electrolyte to improve the interface compatibility between the solid electrolyte and electrode. The lithium ion migration number ( t + ) of the PLG electrolyte membrane is as high as 0.69. At a current density of 200 μA cm −2, the Li|PLG|Li battery can circulate stably for more than 4000 hours. Remarkably, in the LiFePO4 |PLG|Li full battery, good compatibility of the PLG with the electrode can ensure the batteries not only a reversible capacity of 80 mA h g −1 at 25 °C, but also stable cycling of more than 110 days at a rate of 0.5C at 60 °C. Therefore, the addition of LLGO has greatly improved the electrochemical performance of solid-state batteries.