Dendrite-Suppressing Separator with High Thermal Stability Modified by Beaded-Chain-Like Polyimide Coating for a Li Metal Anode

Abstract

Dendritic Li growth is the root hurdle against the implementation of a Li metal anode because it brings safety issues and unsatisfactory efficiency. In this work, a beaded-chain-like polyimide (PI) coating is designed on the commercial polyethylene (PE) separator to suppress the Li dendrite. Owing to the compactly stacking structure and high Li-ion absorption of the PI coating, the wettability of the prepared PI-PE separator is improved and a Li-ion-rich layer with uniform Li-ion transfer channels forms on the surface of the Li metal anode. Therefore, the planar Li deposition rather than dendrite growth has been achieved using this custom separator. The life spans of Cu||PI-PE||Li half-cells have been extended to 7 and 4 times longer than that of Cu||PE||Li half-cells at a current density of 1 mA/cm2 with deposition capacities of 0.5 and 1 mA h/cm2, respectively. Besides suppressing Li dendrites, the multifunctional PI-PE separator also delivers a higher thermal stability to 120 °C than commercial PE and Al2O3-PE separators. This facile approach provides a feasible strategy to realize smooth lithium deposition, and the fundamental mechanism underlying the combination of pore structure and surface chemistry may lead to new approaches to tackle the dendritic problem of Li deposition.

Direct Ink Printing of PVdF Composite Polymer Electrolytes with Aligned BN Nanosheets for Lithium-Metal Batteries

“…When the hot-plate temperature was increased to 300 °C, the CPE-BN film was reduced by just 3.3% compared to CPE by 33.3%. The results indicate that the CPE-BN film can disseminate thermal stress due to its high thermal conductivity, thus enduring high temperature and delivering better thermal stability than the CPE . Thermogravimetric analysis of the printed electrolytes shows improved thermal stability of the CPE-BN electrolytes compared to CPE (Figure S15).…”

“…The results indicate that the CPE-BN film can disseminate thermal stress due to its high thermal conductivity, thus enduring high temperature and delivering better thermal stability than the CPE. 39 Thermogravimetric analysis of the printed electrolytes shows improved thermal stability of the CPE-BN electrolytes compared to CPE ( Figure S15 ). The enhanced thermal stability of the CPE-BN is beneficial for minimizing the short circuit events at high temperatures.…”

Growth Mechanism of Micro/Nano Metal Dendrites and Cumulative Strategies for Countering Its Impacts in Metal Ion Batteries: A Review

“…The systematic coating of Si nanoparticles and polyacrylic acid (PAA) over the separator surface yields a stable, highly conductive passivation layer comprising Li-Si alloy and LiPAA [356]. Various functional modifications and catalyst additions to the separator reinforce the stability of the separator-electrolyte species interface, contributing to higher efficiency and reduced dendrite evolution [357,358]. The self-healing approach intrinsically modulates the protective layers to repair itself, owing to the material's significant endurance.…”

Electrospun polyimide nanofiber‐based separators containing carboxyl groups for lithium‐ion batteries

“…21 Yin et al prepared a beaded-chain-like PI-coated PE separator to suppress Li dendrites. 23 Dong et al prepared PI core and TiO 2 nanoshell nanofiber separator through electrospinning to enhance its ionic conductivity and thermal stability. 24 Numerous methods for fabricating PI composite materials have been reported to enhance separator performance.…”

“…Miao et al prepared a PI nanofiber nonwoven separator through electrospinning 21 . Yin et al prepared a beaded‐chain‐like PI‐coated PE separator to suppress Li dendrites 23 . Dong et al prepared PI core and TiO 2 nanoshell nanofiber separator through electrospinning to enhance its ionic conductivity and thermal stability 24…”