Investigation of Ion Diffusion in Peo-Based Solid Electrolyte with Functionalized La(Oh)3 Nanofibers for High-Rate All-Solid-State Lithium-Metal Batteries
40 Pages Posted: 23 Dec 2024
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Investigation of Ion Diffusion in Peo-Based Solid Electrolyte with Functionalized La(Oh)3 Nanofibers for High-Rate All-Solid-State Lithium-Metal Batteries
Abstract
Solid polymer electrolytes are considered promising candidates for next-generation lithium metal batteries, offering advantages such as improved safety and energy density. However, their practical application is often limited by sluggish ion kinetics and limited Li+ selective transport. This study addresses these challenges by integrating functionalized La(OH)3 nanofibers with oxygen vacancies into a Poly(ethylene oxide) (PEO)-based solid electrolyte to develop high-performance composite electrolytes. The La(OH)3 nanofibers are synthesized using a straightforward method, and their oxygen vacancies effectively capture TFSI- anions from lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), thereby promoting faster Li+ migration. Additionally, the amino groups on La(OH)3 act as Lewis bases, enhancing the dissociation of lithium salts and providing additional pathways for ion conduction. Density functional theory (DFT) and molecular dynamics (MD) simulations confirm that the functionalized La(OH)3 restricts the movement of TFSI-, lowering the energy barrier for Li+ migration and significantly increasing the Li+ transference number to 0.51. The composite electrolyte exhibits excellent performance in Li||Li cells, maintaining stable cycling for over 600 hours at a current density of 0.38 mA cm−2. Furthermore, a solid-state LiFePO4||Li battery demonstrates highly reversible capacities of 100.2 mAh g−1 after 600 cycles at 8 C. These results offer a viable pathway to high-performance solid-state batteries and introduce a novel method for enhancing ionic conductivity through anion confinement using functional group electronic effects.
Keywords: Anion confinement, Li+ transport, All-solid-state lithium batteries, Poly(ethylene oxide), La(OH)3 nanofibers
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