A gel polymer electrolyte functionalized separator for high-performance lithium-sulfur batteries.

Lithium-sulfur (Li-S) batteries, featuring ultrahigh specific theoretical energy density with low-cost raw materials, have been deemed one of the most promising candidates for next-generation energy storage and conversion devices. However, the shuttle effect of soluble Li polysulfides (LiPSs) has seriously hindered their practical deployment. Herein, we report that tris(pentafluorophenyl)borane (TPFPB) is used to modify the separator (TPFPB/Al2O3) for suppressing the shuttle effect of LiPSs. In detail, the introduction of TPFPB induces 1,3-dioxolane solvent ring-opening polymerization to form a gel layer between the S cathode and separator for suppressing the shuttle effect of Li polysulfides, effectively improving the electrochemical performance of Li-S batteries. The Li-S batteries using the TPFPB/Al2O3 separator demonstrate outstanding cycling stability and high capacity retention rates. This work provides a useful guideline for separator modification using a functional interface layer to design high-performance Li-S batteries.

Scalable Customization of Crystallographic Plane Controllable Lithium Metal Anodes for Ultralong-Lasting Lithium Metal Batteries.

A formidable challenge to achieve the practical applications of rechargeable lithium (Li) metal batteries (RLMBs) is to suppress the uncontrollable growth of Li dendrites. One of the most effective solutions is to fabricate Li metal anodes with specific crystal plane, but still lack of a simple and high-efficient approach. Herein, a facile and controllable way for the scalable customization of polished Li metal anodes with highly preferred (110) and (200) crystallographic orientation (donating as polished Li(110) and polished Li(200), respectively) by regulating the times of accumulative roll bonding, is reported. According to the inherent characteristics of polished Li(110)/Li(200), the influence of Li atomic structure on the electrochemical performance of RLMBs is deeply elucidated by combining theoretical calculations with relative experimental proofs. In particular, a polished Li(110) crystal plane is demonstrated to induce Li+ uniform deposition, promoting the formation of flat and dense Li deposits. Impressively, the polished Li(110)||LiFePO4 full cells exhibit unprecedented cycling stability with 10 000 cycles at 10 C almost without capacity degradation, indicating the great potential application prospect of such textured Li metal. More valuably, this work provides an important reference for low-cost, continued, and large-scale production of Li metal anodes with highly preferred crystal orientation through roll-to-roll manufacturability.

Anion-Immobilized Gel Polymer Electrolyte with a High Ion Transference Number for High-Performance Lithium/Sodium Metal Batteries.

Due to their high energy density, lithium/sodium metal batteries (LMBs/SMBs) are expected to be the next generation of energy storage systems. However, the further application of alkali metal batteries based on liquid electrolytes is limited due to increasing safety concerns. Gel polymer electrolytes (GPEs), which combine the advantages of the high ionic conductivity of liquid electrolytes and excellent mechanical properties of solid polymer electrolytes, are considered to play an irreplaceable role in the realization of high-performance alkali metal batteries. In this work, a flexible boron-containing GPE (B-GPE) with a cross-linked polymer network structure is prepared by a UV-induced process. The as-prepared B-GPE exhibits good ionic conductivity and has an extremely high ion transference number due to the electron-withdrawing effect of the boron moiety and the facile electrolyte uptake ability of the ethylene oxide chain. Furthermore, a "gentle" electrode/electrolyte contact is designed by a one-step in situ polymerization method, which can enhance ion transport within the electrode and at the electrode/electrolyte interface due to the presence of a continuous polymer phase for ion conduction. Therefore, LMBs and SMBs containing B-GPE are able to effectively inhibit the growth of dendrites while exhibiting excellent cycling stability. These comprehensive results indicate that this novel B-GPE possesses potential applications for high-performance alkali metal batteries.

A study on the preparation of polycation gel polymer electrolyte for supercapacitors.

The polycation gel polymer electrolyte (PGPE) is a promising electrolyte material for supercapacitors due to its high ionic conductivity and great flexibility. Herein, we report a novel flexible PGPE film, which is prepared by thermal copolymerization. The superiority of PGPE is attributed to the existence of charged groups in the polymer skeleton. Consequently, the crystallinity of the polymer is effectively reduced, and the migration of the lithium ion is evidently promoted. Moreover, the liquid retention capacity of the film is improved, which enhances its ionic conductivity as well. The reported PGPE exhibits a high ionic conductivity of 57.6 mS cm-1 at 25 °C and a potential window of 0-1.2 V. The symmetrical PGPE supercapacitor (AC/AC) shows 95.21% mass-specific capacitance retention after 5000 cycles at 2 A g-1 with a maximum energy density of 12.8 W h kg-1 and a maximum power density of 5.475 kW kg-1. This study confirms the exciting potential of PGPE for high performance supercapacitors.

A flexible polyelectrolyte-based gel polymer electrolyte for high-performance all-solid-state supercapacitor application.

A simple polymerization process assisted with UV light for preparing a novel flexible polyelectrolyte-based gel polymer electrolyte (PGPE) is reported. Due to the existence of charged groups in the polyelectrolyte matrix, the PGPE exhibits favorable mechanical strength and excellent ionic conductivity (66.8 mS cm-1 at 25 °C). In addition, the all-solid-state supercapacitor fabricated with a PGPE membrane and activated carbon electrodes shows outstanding electrochemical performance. The specific capacitance of the PGPE supercapacitor is 64.92 F g-1 at 1 A g-1, and the device shows a maximum energy density of 13.26 W h kg-1 and a maximum power density of 2.26 kW kg-1. After 10 000 cycles at a current density of 2 A g-1, the all-solid-state supercapacitor with PGPE reveals a capacitance retention of 94.63%. Furthermore, the specific capacitance and charge-discharge behaviors of the flexible PGPE device hardly change with the bending states.