A Flexible Dual‐Ion Battery Based on PVDF‐HFP‐Modified Gel Polymer Electrolyte with Excellent Cycling Performance and Superior Rate Capability

Abstract

Dual‐ion batteries (DIBs) have attracted increasing attention owing to their merits of high working voltage, low cost, and especially environmental friendliness. However, the cycling stability of most DIBs is still unsatisfying due to the decomposition of conventional liquid carbonate electrolytes under high working voltages. Exploration of gel polymer electrolytes (GPEs) with good electrochemical stability at high voltage is a possible strategy to optimize their cycling stability. A high‐performance flexible DIB based on a poly(vinylidene fluoride‐hexafluoro propylene) GPE codoped with poly(ethylene oxide) and graphene oxide via weak bond interactions is herein reported for the first time. The prepared polymer electrolyte shows a 3D porous network with significantly improved ionic conductivity up to 2.1 × 10−3 S cm−1, which is favorable for fast ionic transportation of both cations and anions. As a result, this DIB exhibits excellent cycling stability with a capacity retention of 92% after 2000 cycles at a high current rate of 5C (1C is corresponding to 100 mA g−1), which is among the best performances of DIBs. Moreover, good flexibility and thermal stability (up to 90 °C) are also achieved for this battery, indicating its potential applications for high‐performance flexible energy storage devices.

Flexible Quasi‐Solid‐State Composite Electrolyte Membrane Derived from a Metal‐Organic Framework for Lithium‐Metal Batteries

“…On the contrary, when the mass ratios are higher than 0.8, the ionic conductivity of IUP membrane increases by an order of magnitude. This is because the Li−IL@Uio particles cannot contact with each other when less than 0.4 g fillers are dispersed in PVDF‐HFP matrix, since the PVDF‐HFP has poor Li + transport capability, the ionic conductivities only slightly improve due to the decrease of crystallinity . When more than 0.4 g fillers are added into the polymer matrix, the particles well contact each other, continuous Li + transport channels are formed, therefore, significant increase of ionic conductivity is observed.…”

“…The peaks between 115-123 ppm belong to the À CF 3 group in [TFSI] À . The peaks at 14.48 ppm, 35.66 ppm and 44.89 ppm can be assigned to the À CH 3 group and À CH 2 CH 3 group in [EMIM] + . The peaks between 76-78 ppm belong to the deuterated chloroform solvent.…”

Electrolytes for Dual‐Carbon Batteries

“…The cell exhibited a high discharge capacity of ∼100 mAh g −1 at 500 mA g −1 with an average voltage of 4.0 V and outstanding cycling stability, with a capacity retention of 92 % after 2,000 cycles (Figure b). Moreover, the battery can maintain its high capacity even at curling/folding states or at high temperatures, demonstrating good flexibility and high thermal stability (Figure c and 11d) . Dong et al.…”

“…Chen et al. reported a flexible dual‐ion battery based on a PVDF–HFP/PEO/GO GPE (PEO: poly(ethylene oxide); GO: graphene oxide) soaked with 4 M LiPF 6 /EMC+2 % VC (Figure a) . The cell exhibited a high discharge capacity of ∼100 mAh g −1 at 500 mA g −1 with an average voltage of 4.0 V and outstanding cycling stability, with a capacity retention of 92 % after 2,000 cycles (Figure b).…”

Strategien für kostengünstige und leistungsstarke Dual‐Ionen‐Batterien

“…Pionierarbeiten für Batterien mit festem Polymerelektrolyten leisteten bereits Chen und Mitarbeiter. [28] Insgesamt gesehen haben die DIBs im Vergleich mit den modernen LIBs ein sehr frühes Entwicklungsstadium aber noch nicht überschritten. Weitere Anstrengungen sind nçtig, um die Grundmechanismen besser zu verstehen, Strategien zur Verbesserung der elektrochemischen Leistung zu entwickeln und den intrinsischen Herausforderungen der DIBs Rechnung zu tragen.…”