Scalable Manufacturing of Solid Polymer Electrolytes with Superior Room-Temperature Ionic Conductivity

Research Progress on the Enhancement and Modification of PVDF-Based Polymer Electrolytes and Their Applications in Solid-State Lithium Metal Batteries

Traditional liquid electrolyte-based lithium-ion batteries (LIBs) are constrained by safety risks such as flammability and explosion, as well as a relatively low theoretical specific capacity (~300 mAh g-1). Lithium-metal batteries (LMB), which offer higher energy density and enhanced safety, have emerged as competitive candidates for next-generation lithium-based batteries. As a key component of LMBs, polymer electrolytes are expected to exhibit excellent ionic conductivity, robust mechanical properties, and stable interfacial compatibility with electrode materials. Among the diverse range of polymer electrolytes, polyvinylidene fluoride (PVDF)-based polymer electrolytes stand out due to their unique properties. PVDF, with its high dielectric constant, effectively facilitates lithium salt dissociation and ion migration, while maintaining excellent mechanical flexibility. These characteristics position PVDF-based polymer electrolytes as a promising material for LMBs. This review begins by introducing the classification of polymer electrolytes and the mechanisms of lithium-ion migration within them. It then focuses on PVDF-based polymer electrolytes, systematically discussing the synthetic and modification strategies categorized into four main approaches: composite fabrication, inorganic filler doping, liquid additive modification, and multi-strategy modification. Finally, the challenges and future prospects of PVDF-based polymer electrolytes are reviewed to provide insights for developing high-performance polymer electrolytes in the future.

High-Strength MOF-Based Polymer Electrolytes with Uniform Ionic Flow for Lithium Dendrite Suppression

The uneven formation of lithium dendrites during electroplating/stripping leads to a decrease in the utilization of active lithium, resulting in poor cycling stability and posing safety hazards to the battery. Herein, introducing a 3D continuously interconnected zirconium-based metal-organic framework (MOF808) network into a polyethylene oxide polymer matrix establishes a synergistic mechanism for lithium dendrite inhibition. The 3D MOF808 network maintains its large pore structure, facilitating increased lithium salt accommodation, and expands anion adsorption at unsaturated metal sites through its diverse large-space cage structure, thereby promoting the flow of Li+. Infrared-Raman and synchrotron small-angle X-ray scattering results demonstrate that the transport behavior of lithium salt ion clusters at the MOF/polymer interface verifies the increased local Li+ flux concentration, thereby raising the mobility number of Li+ to 0.42 and ensuring uniform Li+ flux distribution, leading to dendrite-free and homogeneous Li+ deposition. Furthermore, nanoindentation tests reveal that the high modulus and elastic recovery of MOF-based polymer electrolytes contribute to forming a robust, dendrite-resistant interface. Consequently, in symmetric battery systems, the system exhibits minimal overpotential, merely 35 mV, while maintaining stable cycling for over 1800 h, achieving low-overpotential lithium deposition. Moreover, it retains redox stability under high voltages up to 5.3 V.

Epoxy-based multifunctional solid polymer electrolytes for structural batteries and supercapacitors. a short review

The potential applications of epoxy-based solid polymer electrolytes are continually expanding because of their versatile characteristics. These characteristics include mechanical rigidity, nonvolatility, nonflammability, and electrochemical stability. However, it is worth noting that pure epoxy-based solid polymer electrolytes inherently exhibit lower ion transport capabilities when compared to traditional liquid electrolytes. Striking a balance between high mechanical integrity and superior ionic conductivity at room temperature poses a significant challenge. In light of this challenge, this review is dedicated to elucidating the fundamental concepts of epoxy-based solid polymer electrolytes. It will explore various preparation techniques, the incorporation of different nanomaterials into epoxy-based solid polymer electrolytes, and an evaluation of their multifunctional properties. This comprehensive evaluation will cover both mechanical and electrical properties with a specific focus on their potential applications in batteries and structural supercapacitors.

Elastomeric Electrolyte for High Capacity and Long-Cycle-Life Solid-State Lithium Metal Battery

High room-temperature ionic conductivity and good compatibility with lithium metal and cathode materials are prerequisites for solid-state electrolytes used in lithium metal batteries. Here, the solid-state polymer electrolytes (SSPE) are prepared by combining the traditional two-roll milling technology with interface wetting. The as-prepared electrolytes consisting of elastomer matrix and high-mole-loading of LiTFSI salt show a high room temperature ionic conductivity of 4.6×10^-4 S cm^-1 , a good electrochemical oxidation stability up to 5.08 V, and improved interface stability. These phenomena are rationalized with the formation of continuous ion conductive paths based on sophisticated structure characterization including synchrotron radiation Fourier-transform infrared microscopy, wide- and small-angle X-ray scattering. Moreover, at room temperature, the Li||SSPE||LFP coin cell shows a high capacity (161.5 mAh g^-1 at 0.1 C), long-cycle-life (retaining 50% capacity and 99.8% Coulombic efficiency after 2000 cycles), and good C-rate compatibility up to 5 C. This study, therefore, provides a promising solid-state electrolyte that meets both the electrochemical and mechanical requirements of practical lithium metal batteries.