Effect of Residual Solvents on Properties of Composite Solid Electrolytes

Abstract

Solid-state electrolytes (SSEs) can stabilize lithium (Li) metal anodes and achieve high energy density. However, they often suffer from solvent residues during the preparation. The residual solvent will affect the performance of SSEs. In this paper, we take Li1.5Al0.5Ge1.5P3O12 (LAGP)/Poly­(propylene carbonate) (PPC) composite solid electrolyte (CSE) as an example, the content of the solvent residue of CSE prepared by the solution casting method and its effect on performance are investigated. The result reveals that the solvent content decreases with the increase of drying time. It still contains more than 5 wt % solvent even after vacuum drying for 48 h. The presence of residual solvent promotes the binding of lithium ions (Li+) and carbonyls, which is conducive to the transfer of Li+. When the residual solvent content is high, SSE has high ionic conductivity, cycling capacity, and excellent cycling stability. When the solvent content decreases, the electrochemical window becomes wider. This result is of great significance for the future regulation of SSE solvent content.

Preparation and Properties of Gel Polymer Electrolytes with Li1.5Al0.5Ge1.5(PO4)3 and Li6.46La3Zr1.46Ta0.54O12 by UV Curing Process

“…The first one is inert fillers, such as SiO 2 [ 19 , 20 ], TiO 2 [ 21 , 22 ], etc. Adding inert fillers will inhibit the crystallization of the polymer, reduce the crystallinity, make the polymer segment movement more active, and thus improve the ionic conductivity; The other is reactive fillers, such as Li 0.3 La 0.557 TiO 3 (LLZO) [ 2 , 23 ], Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO) [ 24 , 25 ], Li 1+x Al x Ti 2−x (PO 4 ) 3 (LATP) [ 26 , 27 ], Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (LAGP) [ 28 , 29 ], etc. Due to the presence of lithium-ion in these materials, ion conduction can be carried out, thereby improving ionic conductivity.…”

Engineering the Interfacial Compatibility of a Small-Molecule Quinone Cathode toward Stable Quasi-Solid-State Lithium-Organic Batteries

“…Usually, the polymer can be swollen by introducing a solvent or plasticizer, which can significantly increase the conductivity of the polymer electrolytes (PEs) and lower their contact barrier with the electrode materials. − The introduced solvent could be trapped by the polymer network, which can not only reinforce the mechanical properties of PEs but also promote ionic conductivity resulting from the solvent–cation interaction (solvation). In addition, integrating plastic crystals into PEs could decrease crystallinity, thus improving the ionic conductivity.…”