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To optimize the rapid transport of lithium ions (Li+) inside lithium metal batteries (LMBs), block copolymer electrolytes (BCPEs) have been fabricated in situ in LMBs via a one‐step method combining reversible addition‐fragmentation chain transfer (RAFT) polymerization and carboxylic acid‐catalyzed ring‐opening polymerization (ROP). The BCPEs balanced the Li+ coordination characteristics of the polyether‐ and polyester‐based electrolytes to achieve a rapid Li+ migration in the SPEs. The carboxylic acid played a dual role since it both catalyzed the ROP and stabilized the interface. Furthermore, the in situ assembly of LMBs did effectively enable an efficient intercalation/de‐intercalation of Li+ at the electrode/electrolyte interface. The in situ assembled Li/BCPE4/LFP exhibited high‐capacity retention of 92 % after 400 cycles at 1 C. The one‐step in situ fabrication of BCPEs provides a new direction for the design of polymer electrolytes. [ABSTRACT FROM AUTHOR]

A novel polymer electrolyte with mechanically robust and self‐healing properties was fabricated through a dual‐network structure, crosslinked by quadruple hydrogen bonding and chemical bonding. The dynamic ureido‐pyrimidinone (UPy) dimers were the first network in the polymer matrix. This group endows the polymer electrolyte with good self‐healing capacity and improves the reliability and lifetime of the polymer lithium batteries. The crosslinked polyethylene glycol‐bis‐carbamate dimethacrylate (PEGBCDMA) is the second network and guarantees dimensional stability and good mechanical properties of the polymer electrolyte. The dual‐network self‐healing polymer electrolyte (DN‐SHPE) exhibits improved ionic conductivity versus the polymer electrolyte fabricated by poly(ethylene glycol) diacrylate (PEGDA). It has high thermal stability (up to 350 °C) and excellent interfacial stability with the electrodes. When the DN‐SHPE‐based cells were fabricated with LiFePO4 and Li metal, the resulting cells show good reversible specific capacity and considerable rate capability. Moreover, the pouch cell could maintain electrochemical function even under deformation or folding conditions. Doctor heal thyself: A robust and self‐healing polymer electrolyte fabricated through a dual‐network structure which is crosslinked by quadruple hydrogen bonding and chemical bond, shows enhanced ionic conductivity, high thermal and electrochemical stabilities, and good self‐healing properties. This dual‐network self‐healing polymer electrolyte (DN‐SHPE) also exhibits excellent interfacial stability with lithium metal and displays stable cycling performance. [ABSTRACT FROM AUTHOR]

A self‐healing polymer electrolyte fabricated via dual‐network structures, which is crosslinked by quadruple hydrogen bonding and chemical bonds, shows enhanced ionic conductivity, high thermal and electrochemical stabilities, and good self‐healing properties. This dual‐network self‐healing polymer electrolyte also exhibits excellent interfacial stability with lithium metal, and displays stable cycling performance. More information can be found in the Full Paper by D. He, Z. Xue et al. on page 19200. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes based on a novel comb-like copolymer, polyethylene glycol-grafted sulfonated polyether ether ketone (SPEEK- g -PEG), was designed and synthesized through the reaction between partially hydroxyl-functionalized sulfonated polyether ether ketone (SPEEK) and epoxy-functionalized PEG. The resulting SPEEK- g -PEG was fully characterized by FTIR, 1 H NMR, TGA, and DSC. All data proved the successful grafting of PEG onto the SPEEK main chain. The resulting comb-like structure effectively inhibited the crystallization of PEG. After doping with a lithium salt, the obtained SPEEK- g -PEG polymer electrolyte membrane showed an improved ionic conductivity. The effects of chain length and PEG grafting ratio on the ionic conductivity of SPEEK- g -PEG were also investigated by electrochemical impedance spectroscopy (EIS). Moreover, the effect of this comb-like structure on increasing the ionic conductivity is higher than that of SPEEK/PEG blends, making these comb-like SPEEK- g -PEG copolymers attractive for an application in LIBs. [ABSTRACT FROM AUTHOR]

Electrospun fiber-based composite polymer electrolyte membranes (PEMs) with artifically constructed long-range proton conductive channels have been drawn considerable attention due to their promising applications in fuel cells. Herein, high level of superacidic phosphotungstic acid (PWA) coated poly(vinylidene fluoride) (PVDF/PWA) electrospun mat as a new three-dimensional proton conducting network was prepared using a polydopamine-assisted coating method. Polydopamine can homogeneously adhere PWA on the PVDF nanofibers' surface. This new mat was then used to fabricate PEMs after filled with polycation chitosan. With the introduction of the PVDF/PWA network, the obtained chitosan filled composite membrane showed significantly improved proton conductivity, which was about one order of magnitude higher than that of the chitosan filled pure PVDF membrane. Moreover, the chitosan can not only effectively inhibit the leaching out of PWA through the strong static interaction between chitosan and PWA, but also act as an ionomer matrix to further increase the proton transport. The direct methanol fuel cell of the PVDF/PWA composite membrane exhibits a peak power density of 85.0 mW cm −2 , whereas it is only 47.5 mW cm −2 for the membrane without PWA coating. Consequently, this study provides a new strategy to design high-performance PEMs by utilization of solid superacid coated electrospun nanofibers. [ABSTRACT FROM AUTHOR]

A novel microporous polymer electrolyte (MPE) based on poly (vinylidene fluoride) (PVDF)/poly (ethylene oxide) (PEO) star polymer was prepared by a phase inversion technique. The effects of PEO chain length of star polymer and temperature on ionic conductivity of MPE were investigated. The results showed that the ionic conductivity increased generally with the chain length of star polymer arms without any abrupt change. Effects of star polymer mass fraction on electrolyte uptake and leakage were also discussed. The distribution of holes and connectivity was improved with star polymer mass fraction increased, thus resulted in a high ionic conductivity (3.03×10 −3 S cm −1 ) exhibited at room temperature. Moreover, the electrochemical stability window was observed above 5.0 V (vs. Li/Li + ). All these results showed that this MPE could be served as a good candidate for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: Gelled microporous polymer electrolyte (GMPE) was prepared by gelating the liquid phase in pores of poly(vinylidene fluoride) membrane with low molecular weight organogelator, 1,3:2,4-di-O-methyl-benzylidene-d-sorbitol (MDBS). Effects of MDBS concentrations on liquid uptake, leakage and ionic conductivity of GMPEs were investigated. The results demonstrated that GMPE containing a certain amount of MDBS showed dramatic decrease in liquid leakage. In consideration of ionic conductivity combining with liquid leakage, the GMPE with 2.0wt% of MDBS (GMPE-2.0) was used to do further evaluations including electrochemical stability, electrolyte/lithium metal electrode stability and charge/discharge in details. The prepared GMPE-2.0 showed an electrochemical stability window of 4.7V (vs. Li/Li+). Moreover, tests run on Li/GMPE-2.0/LiFePO4 cell showed better result in terms of discharge retention than that of cell using polymer electrolyte without MDBS (7.0% and 15.1% improvement of capacity retention after 100 cycles at discharge rate of 0.1C and 5C, respectively). These results showed that it was a promising method to prepare safe lithium-ion batteries with high durability and high performance for practical use. [Copyright &y& Elsevier]