posted on 2024-02-06, 18:05authored byDeborath M. Reinoso, Carmen de la Torre-Gamarra, Antonio J. Fernández-Ropero, Belén Levenfeld, Alejandro Várez
Despite the progress
made in Li-ion battery components, technology
still faces major challenges. Among them, the development of novel
electrolytes with promising characteristics is required for next-generation
energy storage devices. In this work, rigid hybrid electrolytes have
been prepared by infiltration of an ionic liquid solution (Pyr14TFSI) with a lithium salt (LiTFSI) into a sintered LATP ion-conducting
porous ceramic. The porous ceramic 3D network was obtained via solid-state
sintering of LATP powders mixed with a small amount of corn starch
as pore former. A synergetic effect between the ionic liquid and support
was evidenced. The resultant quasi-solid-state hybrid electrolytes
exhibit high ionic conductivity (∼10–3 S·cm–1 at 303 K), improved ion transfer number, tLi+, and a wide electrochemical
window of 4.7–4.9 V vs Li+/Li. The LATP porosity
plays a critical role in the free Li+ charge because it
favors higher TFSI– confinement in the ceramic interfaces,
which consequently positively influences tLi+ and ionic conductivity. Electrochemical tests
conducted at room temperature for Li/LiFePO4 cells using
the hybrid electrolyte exhibited a high capacity of 150 mAh·g–1LFP at C/30, and still retained 60 mAh·g–1LFP at 1 C, while bare LATP does not perform
well at low temperatures. These findings highlight this hybrid electrolyte
as a superior alternative to the ceramic LATP electrolyte and a safer
option compared with conventional organic electrolytes.