Solid Polymer Electrolytes from Copolymers Based on Vinyl Dimethyl Phosphonate and Vinylidene Fluoride

Abstract

Solid polymer electrolytes are prepared by mixing various amounts of lithium bis(trifluoromethanesulfonyl)imide with poly(vinylidene fluoride‐co‐vinyl dimethyl phosphonate) statistical copolymers with different compositions. Such copolymers are obtained by conventional radical copolymerization of vinylidene fluoride (VDF) with vinyl dimethyl phosphonate (VDMP) initiated by peroxides. A morphological study of the obtained solid polymer electrolytes (SPEs) shows that only samples prepared from the copolymer with the lower amount of VDMP (16 mol%) result in the formation of homogeneous electrolytes while aggregates of lithium salts are observed for the other copolymers. The best ionic conductivity values are accordingly observed for the copolymers with the lower VDMP amount and are reaching 5 × 10−3 mS cm−1 at 100 °C. The dependence of the ionic conductivity versus temperature suggests that the ionic conductivity is controlled by the motion of polymer segments. Indeed, the ionic conductivity can be increased by adding a small amount of trimethylphosphate plasticizer and can reach 1.9 × 10−2 mS cm−1 at 20 °C. Finally, the prepared SPEs exhibit a high electrochemical stability and a good resistance to flame because of the presence of fire‐retardant phosphate groups in their structure.

Copolymers of vinylidene fluoride with functional comonomers and applications therefrom: Recent developments, challenges and future trends

“…First attempts achieved at low temperature failed [63] but more recent success was obtained in presence of 2,5-dimethyl-2,5-di(tert-butylperoxy) hexane (DTBPH) initiator (Scheme 10) leading to rich-VDF cooligomers [64].…”

Solid Polymer Electrolytes Based on Phosphonate and Cyclocarbonate Units for Safer Full Solid State Lithium Metal Batteries

“…[58][59][60] In the case of poly(MAPC1), the ionic conductivity was 3.4 × 10 −7 S cm −1 at room temperature and hardly reached values above 10 −6 S cm −1 at 60 °C, in agreement with our recent study on phosphonatebased SPEs. [42] The use of the phosphonate polymer is thus motivated by its fire-retardant properties rather than ionic conducting properties.…”

“…Those GPEs were tested in sodium‐ion batteries and showed ionic conductivity values around 10 −3 S cm −1 at room temperature, [ 37–39 ] which are comparable to values obtained on nonflammable phosphonate‐containing GPEs based on a poly(vinylidene fluoride‐ co ‐hexafluoropropylene) matrix. [ 40 ] Notwithstanding those previous reports, the use of phosphonate‐based polymers for full solid‐state lithium metal batteries has only been reported by Macarie's, [ 41 ] Gohy's, [ 42 ] Wang [ 43 ] and Mercerreyes's [ 44 ] groups to the best of our knowledge.…”

Development of a New Crosslinked Highly Conductive Hybrid Electrolyte based on Polyetherdiamine, Diphenylmethane Diisocyanate and Organosilanes for Efficient Lithium‐Metal Battery

“…However, ionic conductivity of 10 −4 S cm −1 at ambient temperature is hardly achievable with this type of electrolytes because of crystallization effect and thus reduces the possibility of using them in LMBs. Therefore, a variety of modified polymer electrolytes, such as blend based, branched polymer based, semi‐interpenetrating networked based, block co‐polymer based and composite polymer electrolytes made with micron or nanosized filler particles have been synthesized with the aims of enhancing the ionic conductivity [14–18] . However, the disadvantages associated with some of the SPEs, such as poor mechanical property and electrochemical stability, and particle aggregation in composite polymer electrolytes, prohibit their practical use in LMBs.…”

“…Therefore, a variety of modified polymer electrolytes, such as blend based, branched polymer based, semi-interpenetrating networked based, block co-polymer based and composite polymer electrolytes made with micron or nanosized filler particles have been synthesized with the aims of enhancing the ionic conductivity. [14][15][16][17][18] However, the disadvantages associated with some of the SPEs, such as poor mechanical property and electrochemical stability, and particle aggregation in composite polymer electrolytes, prohibit their practical use in LMBs. Therefore, there is a growing interest to develop a SPE free from these drawbacks.…”