An acrylate-based quasi-solid polymer electrolyte incorporating a novel dinitrile poly(ethylene glycol) plasticizer for lithium-ion batteries

Abstract

The performance of solid polymer electrolytes is characterized by lower ionic conductivity than conventional liquid electrolytes but provides advantages in terms of operational safety. A quasi-solid polymer electrolyte (QSPE) based on a new plasticizer 4,7,10,13-tetraoxahexadecane-1,16-dinitrile (bCN-PEG4) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) incorporated into a polyacrylates matrix was successfully prepared via UV-induced copolymerization. The matrix consists of units of trimethylolpropane ethoxylate triacrylate (ETPTA), poly(ethylene glycol) diacrylate (PEGDA), and the monoacrylate poly(ethylene glycol) methyl ether acrylate (mPEGa). The QSPE containing 55 wt% bCN-PEG4 exhibits highly uniform morphology, thermal stability > 200 °C, ionic conductivity of 1.8 × 10−4 S cm−1 at 30 °C, and 1.3 × 10−3 S cm−1 at 80 °C, coupled with very high electrochemical stability (> 5 V vs. Li/Li+) and a low glass transition temperature (− 55.7 °C). A cycling experiment in a Li/QPSE/Li cell setup demonstrated the compatibility toward lithium metal additionally. The bCN-PEG4 offers an overall satisfying performance as a plasticizer in a poly(ethylene oxide)-based solid polymer electrolyte. The new QSPE is an alternative to dinitrile-based (e.g., succinonitrile) or glycol ether-based (e.g., tetraglyme) plasticizers with application potential in high-voltage lithium-ion batteries. Graphical abstract

Functionality of 1‐Butyl‐2,3‐Dimethylimidazolium Bromide (BMI‐Br) as a Solid Plasticizer in PEO‐Based Polymer Electrolyte for Highly Reliable Lithium Metal Batteries

“…Therefore, the weight loss of the electrolytes was accelerated with increased BMI‐Br content. [ 63 ] In conclusion, BMI‐Br‐10 CPE exhibited high thermal stability up to 347.85 °C. This property makes the polymer electrolytes suitable for various applications in LMBs with an operating temperature of 0–45 °C.…”

An ambient‐temperature superionic conductive, electrochemically stable, plastic cross‐linked polymer electrolyte for lithium metal battery

“…Figure S2a shows the highly homogeneous and smooth surface of the electrolyte SPE50 with no wrinkles or pores, indicating a homogeneous morphology without phase separation. 25 Figure S2b,c are cross-sectional images of SPE50 magnified at different magnifications, showing the compact and dense polymer film structure. The film structure is important to prevent the growth of lithium dendrites, since the growth of lithium dendrites leads to irregularities at the electrode/electrolyte interface (localized current density nonuniformity during cell cycling).…”

A Roadmap for Solid‐State Batteries

“…This is, mixing inorganic or polymer SE (main phase) with ionic liquids (e.g., PYRxTFSI), [234,[244][245][246][247] LE, [248,249] or organic liquids (e.g., ethers, carbonates, glycols). [250][251][252] Polymer matrices, which absorb LE as the main conducting phase, are called gel polymer electrolyte for historical reasons. [93,253,254] Due to the use of liquid or gel electrolytes, hybrid liquid-solid battery concepts can solve remaining issues, both in cell design and in production, and especially have advantages in a timely scale-up compared to ASSB concepts.…”