Thermally Stable PVDF-HFP-Based Gel Polymer Electrolytes for High-Performance Lithium-Ion Batteries

Abstract

The development of gel polymer electrolytes (GPEs) for lithium-ion batteries (LIBs) has paved the way to powering futuristic technological applications such as hybrid electric vehicles and portable electronic devices. Despite their multiple advantages, non-aqueous liquid electrolytes (LEs) possess certain drawbacks, such as plasticizers with flammable ethers and esters, electrochemical instability, and fluctuations in the active voltage scale, which limit the safety and working span of the batteries. However, these shortcomings can be rectified using GPEs, which result in the enhancement of functional properties such as thermal, chemical, and mechanical stability; electrolyte uptake; and ionic conductivity. Thus, we report on PVDF-HFP/PMMA/PVAc-based GPEs comprising poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) and poly(methyl methacrylate) (PMMA) host polymers and poly(vinyl acetate) (PVAc) as a guest polymer. A physicochemical characterization of the polymer membrane with GPE was conducted, and the electrochemical performance of the NCM811/Li half-cell with GPE was evaluated. The GPE exhibited an ionic conductivity of 4.24 × 10−4 S cm−1, and the NCM811/Li half-cell with GPE delivered an initial specific discharge capacity of 204 mAh g−1 at a current rate of 0.1 C. The cells exhibited excellent cyclic performance with 88% capacity retention after 50 cycles. Thus, this study presents a promising strategy for maintaining capacity retention, safety, and stable cyclic performance in rechargeable LIBs.

Phase behavior of binary and ternary fluoropolymer (PVDF-HFP) solutions for single-ion conductors

“… a LPF : PEO = 1 : 3.57 (wt ratio) indicates that the 20 repeat units of PEO per repeat unit of LPF. 21 …”

“…For example, PVDF-HFP has been blended with other molecules such as poly(ethylene oxide) (PEO), poly(methyl methacrylate) (PMMA), poly(vinyl acetate) (PVAc), poly(vinyl chloride) (PVC), thermoplastic polyurethane (TPU), poly(methyl methacrylate-co-acrylonitrile-co-lithium methacrylate) (PMAML), poly(ionic liquid), polysiloxane, and carboxymethyl cellulose (CMC). 8,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] Here, it is notable that these polymer electrolytes have been developed for solid-state batteries (SSBs), which are one of the post-lithium-ion batteries (PLIBs) including sodium-ion batteries (SIBs), lithium-sulfur batteries (LSBs), and lithium-air batteries (LABs). [27][28][29][30][31][32] Specically, the peruoropolyether-based block copolymer electrolyte was designed for ultra-stable SIBs.…”

Review of Materials for Electrodes and Electrolytes of Lithium Batteries

“…High crystallinity of PEO at room temperature prevents the movement of chain segments, and PEO ionic diffusion capability are not ideal. Many other types of polymers have been developed as the basis of electrolytes, such as PAN [77], PC [78], polymethyl methacrylate (PMMA) [76,79,80], PVDF [13,74], and PVDF-HFP [81][82][83]. Among them, PVDF and PVDF-HFP materials are very promising as solid electrolytes for lithium batteries due to their higher dielectric constant, chemical stability, and higher mechanical strength [74].…”

Silicon Layer on Polymer Electrolyte as a Dendrite Stopper for Stable Lithium Metal Batteries

“…Additionally, a thin metal-tungsten interlayer on the surface of lithium metal has been demonstrated to facilitate the uniform deposition of lithium ions through a lithium–tungsten alloying reaction. − However, the softness of the lithium metal surface, the complex fabrication process, and strict environmental requirements severely hinder the development of artificial coatings on the surface of the lithium metal. Therefore, the construction of artificial coatings on polymer electrolytes has been a better choice. − In general, polymer electrolytes display insufficient mechanical strength to resist the growth of lithium dendrites . An effective approach to resist dendrite growth is to construct artificial coatings on the surface of polymer electrolytes for uniform lithium-ion deposition.…”