Lithium Ionic Conductive Mechanism in PEO Polymer Electrolytes Enhanced by Nano/Micron Size LLZO Fillers

Abstract

Solid polymer electrolytes (SPEs) incorporating inorganic ceramic fillers are key solutions of all solid-state lithium battery technology applications. At present, the conductive mechanism of LLZO-PEO electrolyte is still controversial. Herein, the effect of nano and micron LLZO on the conductive mechanism of PEO matrix with different molecular weight is studied. The low molecular weight PEO electrolyte (LSPEs) containing nano LLZO exhibit higher conductivities than those with the micron ones, which is primarily caused by the percolation effect resulting from the difference in specific surface area. However, for high molecular weight PEO electrolytes (HSPEs), the addition of nano LLZO ceramic fillers can mainly lead to reduce the crystallinity of HSPEs to enhance the motion of polymer segment. Thus, compared with HSPEs alone, the nano LLZO-HSPEs show conductivities one order of magnitude larger. Besides, the discharge capacity of nano LLZO-HSPEs based LiFePO4/Li batteries at 1 C is around 131 mAh g-1 at 60 oC, as well as discharge specific capacity holds 99.2% after 200 cycles. Notably, nano LLZO ceramic fillers will enhance cyclic performance of LiFePO4/Li batteries at 0.2 C and 40 oC, which still maintain 126.7 mAh g-1 after 50 cycles.

Softening of PEO–LiTFSI/LLZTO Composite Polymer Electrolytes for Solid-State Batteries under Cyclic Compression

“…While similar findings showing higher conductivity for smaller particles have been reported for other PEO-based composite electrolytes, – these data uniquely show a difference in the sensitivity of ionic conductivity to particle size, when subjected to repetitive mechanical deformation. That is, the smaller particles are associated with higher ionic conductivity but are also more prone to proportional loss of conductivity when subjected to repetitive mechanical loading.…”

Ionic Conductivity and Cycling Performance in PEO Polymer Electrolyte Enhanced by Non-Milled In Situ Nano-LLZO Powders

“…In order to further investigate the effect of non-milled and milled LLZO on the electrochemical performance of composite electrolyte, we design these experiments of Sections and 3.5. Extensive research studies suggest that the ionic conductivity of 7.5% LLZO–PEO electrolyte reaches maximum value. ,, These research studies in the literature references set a series of LLZO concentrations in PEO electrolytes and measure their ionic conductivities. The ionic conductivity of 7.5% LLZO–PEO electrolyte is proved to be the highest value.…”

“…Extensive research studies suggest that the ionic conductivity of 7.5% LLZO−PEO electrolyte reaches maximum value. 31,38,39 These research studies in the literature references set a series of LLZO concentrations in PEO electrolytes and measure their ionic conductivities. The ionic conductivity of 7.5% LLZO− PEO electrolyte is proved to be the highest value.…”

Solid-state composite electrolytes: turning the natural moat into a thoroughfare

“…7d, which gives one order of magnitude higher conductivity than the pristine high-molecular weight PEO polymer electrolyte. 89 Using only one size of active fillers may be of limited help in improving the ionic conductivity. Sun et al studied the effect of mixed-size LLZO fillers in improving the ionic conductivity of PVDF-LiClO 4 -based SCEs.…”