Uniform Lithium Plating for Dendrite-Free Lithium Metal Batteries: Role of Dipolar Channels in Poly(vinylidene fluoride) and PbZr_xTi_1–xO₃ Interface

Abstract

Conventional polymer/ceramic composite solid-state electrolytes (CPEs) have limitations in inhibiting lithium dendrite growth and fail to meet the contradictory requirements of anodes and cathodes. Herein, an asymmetrical poly­(vinylidene fluoride) (PVDF)–PbZr x Ti1–x O3 (PZT) CPE was prepared. The CPE incorporates high dielectric PZT nanoparticles, which enrich a dense thin layer on the anode side, making their dipole ends strongly electronegative. This attracts lithium ions (Li+) at the PVDF–PZT interface to transport through dipolar channels and promotes the dissociation of lithium salts into free Li+. Consequently, the CPE enables homogeneous lithium plating and suppresses dendrite growth. Meanwhile, the PVDF-enriched region at the cathode side ensures intermediate contact with positive active materials. Therefore, Li/PVDF-PZT CPE/Li symmetrical cells exhibit a stable cycling performance exceeding 1900 h at 0.1 mA cm–2 at 25 °C, outperforming Li/PVDF solid-state electrolyte/Li cells that fail after 120 h. The LiNi0.8Co0.1Mo0.1O2/PVDF–PZT CPE/Li cells show low interfacial impedances and maintain stable cycling performance for 500 cycles with a capacity retention of 86.2% at 0.5 C and 25 °C. This study introduces a strategy utilizing dielectric ceramics to construct dipolar channels, providing a uniform Li+ transport mechanism and inhibiting dendrite growth.

A Dielectric MXene‐Induced Self‐Built Electric Field in Polymer Electrolyte Triggering Fast Lithium‐Ion Transport and High‐Voltage Cycling Stability

“…In the broadband dielectric spectroscopy (BDS) test, the dielectric constant experiences a significant increase, with the real dielectric permittivity (ϵr′) rising from 16 for PPTE to 46 for PPTE‐Nb 4 C 3 F 2 , and the imaginary dielectric permittivity (ϵr′′) increasing from 28 for PPTE to 142 for PPTE‐Nb 4 C 3 F 2 at 1 Hz under 30 °C. According to earlier findings, the elevated dielectric constant of QPE aids can intensify the charge separation of dipoles, facilitating the dissociation of Li salts [13a,17] . Additionally, the fluorinated MXene (Nb 4 C 3 F 2 ) enhances safety by improving the thermal stability of electrolytes and reducing the flammability of battery components (Figure S20).…”

Solid-state polymer electrolytes in lithium batteries: latest progress and perspective

“…Such a polymer with large dipole moments can guide lithium cations (Li + ) to align along the chain, forming a continuous pathway for Li + hopping within SSEs. 179 Similarly, Kang et al enriched the dense thin layer on the anode side by incorporating highly dielectric asymmetrical poly(vinylidene fluoride)(PVDF)-PbZr x Ti 1− x O 3 (PZT) nanoparticles with strong electronegativity at the dipole end. As shown in (Fig.…”

Solid‐State Electrolytes and Electrode/Electrolyte Interfaces in Rechargeable Batteries

“…[143] Moreover, PVdF is easily soluble in conventional organic solvents and compatible with Li metal electrodes, thus the PVdF-based electrolyte can be prepared as a uniform membrane by solution casting or electrospinning. [144] However, PVdF has a semi-crystalline chain and low liquid electrolyte up-take abilities, thus, an amorphous HFP polymer segment is usually introduced into PVdF to break the regular segment structure and increase the ionic conductivity of the electrolytes. The increase of À CÀ FÀ bonds in the HFP chain leads to good thermal/chemical endurance and higher electrochemical stability of the PVdF-HFP-based electrolytes.…”