Carbon dots crosslinked gel polymer electrolytes for dendrite‐free and long‐cycle lithium metal batteries

Abstract

Lithium metal batteries (LMBs) with extremely high energy densities have several advantages among energy storage equipment. However, the uncontrolled growth of dendrites and the flammable liquid electrolytes (LEs) often cause safety accidents. All solid-state batteries seem to be the ultimate choice, but solvent-free electrolytes usually fail in terms of conductivity at room temperature. Therefore, gel polymer electrolytes (GPEs) with a simple manufacturing process and high ionic conductivity are considered as the most competitive candidates to resolve the present difficulties. Herein, we design a polymeric network structure via esterification and amidation reactions between polyethylene glycol (PEG) and carbon dots (CDs). After incorporation with polyvinylidene fluoride and some LEs, the as-prepared PEG-CDs composite electrolytes (PCCEs) show a high ionic conductivity of 5.5 mS/cm and an ion transference number of 0.71 at room temperature, as well as good flexibility and thermostability. When the PCCEs are assembled with lithium metal anodes and LiFePO 4 or LiCoO 2 cathodes, both the cycling stability and the retention rate of these LMBs show excellent performance at room temperature.

Interfacial Interaction of Multifunctional GQDs Reinforcing Polymer Electrolytes For All‐Solid‐State Li Battery

“…A major feature of graphene quantum dots is their high conductivity, which is unfavorable for the application of electrolytes. [ 21 ] The electronic conductivity of polymer films was tested by DC polarization. Due to the quite low additive amount and the existence of functional groups of GQDs, as shown in Figure S6 (Supporting Information), the electronic conductivity is slightly enhanced with the presence of GQDs, but it still remained at a very low level, so that it can be considered that CPE is still insulated.…”

Practical challenges and future perspectives of solid polymer electrolytes: microscopic structure and interface design

“…), ferroelectric characteristics, electrical conductivity, and other factors of the solid fillers play a positive impact on the comprehensive performance of SPEs. [115][116][117][118] Related research works will be summarized in detail in the following section of 2.2.2.…”

Lithiophilic hyperbranched Cu nanostructure for stable Li metal anodes

“…The developments of electric facilities, like intelligent grids, electric vehicles, and portable electronics, necessitate electrochemical energy storage with high energy densities 1–5 . Owing to the high gravimetric capacity of 3860 mAh/g and ultralow redox potential of −3.04 V (vs. standard hydrogen electrode), metallic lithium (Li) has been regarded as one of the most promising anodes that may meet the ever‐increasing requirements of high energy density for next‐generation batteries 6–15 .…”

“…The developments of electric facilities, like intelligent grids, electric vehicles, and portable electronics, necessitate electrochemical energy storage with high energy densities. [1][2][3][4][5] Owing to the high gravimetric capacity of 3860 mAh/g and ultralow redox potential of −3.04 V (vs. standard hydrogen electrode), metallic lithium (Li) has been regarded as one of the most promising anodes that may meet the ever-increasing requirements of high energy density for next-generation batteries. [6][7][8][9][10][11][12][13][14][15] However, Li metal anodes (LMAs) suffer from an uncontrollable growth of Li dendrites and volume expansion of Li metals, which significantly restricts the commercialization step to the practical applications.…”