Weng Jingzheng

Bio: Weng Jingzheng is an academic researcher from Fujian Normal University. The author has contributed to research in topics: Lithium & Ceramic. The author has co-authored 3 publications.

Highly Conductive and Thermostable Grafted Polyrotaxane/Ceramic Hybrid Polymer Electrolyte for Solid-State Lithium-Metal Batteries.

Abstract: Although polymer electrolytes have been regarded as potential separator materials for high energy density solid-state lithium-based batteries, their applications were significantly restricted by the low ionic conductivity, poor mechanical strength, and thermostability. Herein, a highly conductive and thermostable hybrid polymer electrolyte was developed by combining poly(vinylidene fluoride-co-hexafluoropropylene)-grafted polyrotaxane and nano-Al2O3 particles. In this unique hybrid, not only the Lewis acid-type Al2O3 and the fluorine groups of polyrotaxane branches exhibited strong integration with ionic species to accelerate the dissociation of lithium salt, improving the Li ionic conductivity, but also the abundant hydroxy functional groups on the surface of Al2O3 hydrogen-bonded with fluorine-containing branches, enhancing the mechanical strength. More importantly, the hybrid electrolyte exhibited superior thermal stability due to the heat resistance of the ceramic filler and the unique bead string structure of polyrotaxane. Consequently, a polymer electrolyte with a comprehensively improved performance was obtained, including high ionic conductivity and Li+ transfer number and superior tensile strength and thermostability. The hybrid electrolyte provided a dendrite-free lithium anode with a long life up to 1800 h and stable solid-state lithium-metal batteries at a high temperature of 80 °C.

Influence of Binder on Impedance of Lithium Batteries: A Mini-review

Abstract: As an integral component of electrodes, binder is one of the key factors for improving of the performance and prolonging the service life of lithium batteries. To predict the service life of lithium batteries, observing the impedance evolution of batteries during the cycling process has been considered as a promising strategy. Electrochemical impedance spectroscopy as an effective measurement has been applied in numerous studies to explore the impedance behavior of lithium batteries. Therefore, this paper reviews the influencing factors of the impedance variation during charging and discharging processes and the influence of various binders on the impedance performance of lithium-ion batteries. Moreover, an outlook is proposed for the modification of binders to improve the performance of lithium-ion batteries.

Thermal stability and thermal conductivity of solid electrolytes

Abstract: Compared with liquid organic lithium-ion batteries, solid-state lithium-ion batteries have higher safety performance, so they are expected to become the next generation of energy storage devices and have attracted extensive research attention. The thermal management of the battery is a multi-coupling problem. Battery safety, cycle life, and even electrochemical reactions are all related to it. This Perspective presents the commonly used solid-state electrolytes and recent studies on their thermal stability and thermal transport properties. The thermal decomposition temperature and thermal conductivity are summarized, and we also present the summary and a brief outlook. This Perspective provides a reference for how to design and select high thermal conductive electrolyte materials, which is important for further advancement of solid-state lithium-ion batteries.

A flexible network polyimides binder for Si/graphite composite electrode in lithium‐ion batteries

Abstract: Although the high‐capacity Si/graphite anode serves to advance the energy density of lithium‐ion batteries, the volume change remains the main disfigurement of Si/graphite anode. Many studies show that crosslinked structure binders tend to play a good inhibitory effect on volume expansion. In this work, a three‐dimensionally covalently cross‐linked and flexible polyimides (C–PI–OH) is successfully synthesized and applied as silicon/graphite anode, which is composed through a tri‐monomer co‐polycondensation and crosslinking process. The as‐formed free carboxylic acid groups and amide groups in C–PI–OH are efficient in structural stability, so the electrode bound by C–PI–OH exhibits the highest peeling strength than C–PI and polyvinylidene fluoride. The flexible network of the C–PI–OH binder is competent for accommodating the volume expansion and contraction of silicon particles during the deintercalation of lithium ion, which helps in the wholeness of solid electrolyte interface film and electrodes, and effectively boosting the cycle stability of the Si/graphite anode.