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To realize high-energy-density Li metal batteries at low temperatures, a new electrolyte is needed to solve the high-voltage compatibility and fast lithium-ion de-solvation process. A gel polymer electrolyte with a small-molecular-weight polymer is widely investigated by combining the merits of a solid polymer electrolyte (SPE) and liquid electrolyte (LE). Herein, we present a new gel polymer electrolyte (P-DOL) by the lithium difluoro(oxalate)borate (LiDFOB)-initiated polymerization process using 1,3-dioxolane (DOL) as a monomer solvent. The P-DOL presents excellent ionic conductivity (1.12 × 10−4 S cm−1) at −20 °C, with an oxidation potential of 4.8 V. The Li‖LiCoO2 cell stably cycled at 4.3 V under room temperature, with a discharge capacity of 130 mAh g−1 at 0.5 C and a capacity retention rate of 86.4% after 50 cycles. Moreover, a high-Ni-content LiNi0.8Co0.1Mn0.1O2 (NCM811) cell can steadily run for 120 cycles at −20 °C, with a capacity retention of 88.4%. The underlying mechanism of high-voltage compatibility originates from the dense and robust B- and F-rich cathode interface layer (CEI) formed at the cathode interface. Our report will shed light on the real application of Li metal batteries under all-climate conditions in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] Solid-state polymer electrolytes are outstanding candidates for next-generation lithium metal batteries in the realm of high specific energy densities, high safeties and tight contact with electrodes. However, their applications are still hindered by the limitations that no single polymer is electrochemically stable with the oxidizing high-voltage cathode and the highly reductive Li anode, simultaneously. Herein, a bilayer asymmetric polymer electrolyte (SL-SPE) without accessional interface resistance that using poly (ethylene glycol) diacrylate (PEGDA) as a "bridge" to connect the sulfonyl (O S = O)-contained oxidation-tolerated layer and polyether-derived reduction-tolerated layer (SPE), is proposed and synthesized by sequential two-step UV polymerizations. SL-SPE can provide widened electrochemical stability window up to 5 V, while simultaneously deploying a stable Janus interface property. Eventually, the superior high-voltage (4.4 V) cycling durability can be displayed in LiNi 0.6 Co 0.2 Mn 0.2 O 2 |SL-SPE|Li batteries. This finding provides a bran-new idea for designing multifunctional polymer electrolytes in the application of solid-state batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] Polyvinylidene difluoride (PVDF) is one of the most attractive electrolyte materials for solid-state batteries due to its high ionic conductivity, however, the battery performance is limited by the high electrolyte–electrode interfacial resistance. Herein, PVDF polymer mixed with ceramic Li 7 La 3 Zr 2 O 12 is coated on cellulose support membrane (PLCSM) through a simple slurry-casting method. The ionic transport of PLCSM is originated from dimethyl formamide (DMF)-Li+ solvation structure, which plays a critical role in conducting lithium ions. β-PVDF after dehydrofluorination offers a high dielectric constant and enhances the dissociation of lithium salt. As a result, PLCSM with a total thickness of 85 µm presents an oxidation voltage of 4.9 V. Li-Li symmetric cells by employing PLCSM reveal that the critical current density (CCD) is increased to 1 mA cm−2. A full cell of LiFePO 4 |PLCSM |Li with high mass loading (1.2 mA h cm−2) shows a first-cycle discharge capacity of 160 mA h g−1. With LiNi 0.6 Mn 0.2 Co 0.2 O 2 as the cathode, the initial discharge capacity is 153 mA h g−1, and the capacity retention after 80 cycles is 80 %. The sandwiched PLCSM provides an effective strategy to achieve high-performance dendrite-free Li metal batteries. [ABSTRACT FROM AUTHOR]

A quasi-solid-state Li-Te battery was developed using a flexible gel polymer electrolyte and Te/C cathode. [Display omitted] A quasi-solid-state Li-Te battery is developed by using a flexible gel polymer electrolyte (GPE), porous carbon/tellurium cathode, and lithium metal anode. The ionic conductivity of GPE is controllable and reaches up to 8.0 × 10−4 S cm−1 at 25 °C. The good interfacial contact with Li metal ensures excellent cycling stability in Li/GPE/Li symmetric cells. Moreover, it is found that, compared to S and Se counterparts, the Li-Te battery exhibits good rate capability due to the high electrical conductivity of Te and excellent interfacial stability among GPE, Li, and Te. This work provides several facile strategies to develop safe and high-performance solid-state Li-Te batteries. [ABSTRACT FROM AUTHOR]

Block copolymer electrolytes (BCPEs) are promising candidates for solid-state lithium battery applications because they can achieve improved mechanical performance and conductivity simultaneously. In this report, we report on fluorine-containing ABA triblock copolymer electrolytes (FBCPEs) with A blocks of perfluoroalkyl pendants and B blocks of poly(ethylene oxide) (PEO). It is found that fluorine-containing blocks endows considerable mechanical strength, high lithium ion transference number of t Li+ = 0.41, and wide electrochemical stability window up to 4.9 V to FBCPEs. In addition, FBCPEs can also participate in forming fluorinated solid electrolyte interphase (SEI), and thus serves to enhance the cycle stability of batteries. Combination of these excellent properties leads to the LiFePO 4 /FBCPEs/Li cells with excellent cycling performance and rate capability. The cycle results of the assembled LiNi 0.6 Co 0.2 Mn 0.2 O 2 /FBCPEs/Li cells indicate that FBCPEs have potential for application in high-voltage battery systems. [Display omitted] • Solid-state fluorine-containing triblock copolymer electrolytes were developed. • High lithium ion transference number and wide electrochemical stability window. • LiFePO 4 cells assembled with FBCPEs exhibit excellent cycling performances. [ABSTRACT FROM AUTHOR]

The low coulombic efficiency and poor cycle performance deriving from uncontrolled growth of dendrites have caused a serious obstacle to the practical application of lithium metal. Herein we propose a bifunctional regular-random dual cross-linking network solid polymer electrolyte (RRa-SPE) for dendrite-free all-solid-state lithium metal batteries. Under the synergistic effect of regular polymerization skeleton and random cross-linking network, the RRa-SPE effectively regulates the lithium deposition and facilitates the generation of a highly homogeneous and robust solid-electrolyte interphase (SEI) layer on lithium metal. Besides, this RRa-SPE shows benign ionic conductivity of 4.36 × 10−4 S cm−1 (at 30 °C), high lithium ion transference number of 0.76 and enhanced mechanical strength. The Li/RRa-SPE/Li symmetric cell maintains low and stable voltage polarization (0.15 V) after circulating for 1200 h at 0.5 mA cm−2. Improved LiFePO 4 /RRa-SPE/Li cell exhibits excellent rate capability and prominent cycle performance with a capacity retention of 99.6% after 240 cycles at 0.5 C at 30 °C. Image 1 The SPE is prepared via a facile UV-derived dual-reaction. With bifunctional network, the SPE effectively regulates the lithium deposition. The SPE shows enhanced ionic conductivity of 4.36 × 10−4 S cm−1 at 30 °C. The SPE exhibits high lithium ion transference number of 0.76. [ABSTRACT FROM AUTHOR]