Yolk–Shell Structured ST@Al₂O₃ Enables Functional PE Separator with Enhanced Lewis Acid Sites for High‐Performance Lithium Metal Batteries

Abstract

Commercial polymer separators usually have limited porosity, poor electrolyte wettability, and poor thermal and mechanical stability, which can deteriorate the performance of battery, especially at high current densities. In this work, a functional polyethylene (PE) separator is prepared by surface engineering a layer of Ti‐doped SiO2@Al2O3 particles (denoted as ST@Al2O3‐PE) with strong Lewis acid property and uniform porous structure on one side of the PE separator. On the other hand, ST@Al2O3 particles with abundant pore structures and large cavities can store a large amount of electrolyte, providing a shortened pathway for lithium‐ion transport, and the Lewis acid sites and porous structure of the ST@Al2O3 can tune Li plating/stripping behavior and stabilize the lithium metal anode. The ST@Al2O3‐PE separators exhibit better ionic conductivity (5.55 mS cm−1) and larger lithium‐ion transference number (0.62). At a current density of 1 mA cm−2, Li/Li symmetric cells with ST@Al2O3‐PE separator can be stably cycled for more than 400 h, and both lithium iron phosphate /Li cells and lithium cobaltate/Li cells with ST@Al2O3‐PE separator have good cycling and rate performance. This work provides a new strategy for developing functional separators and promoting the application of lithium metal batteries.

Vertically Aligned Hollow Mesoporous Silica Rods Enabling Composite Polymer Electrolytes with Fast Ionic Conduction for Lithium Metal Batteries

“…The construction of aligned interfaces provides Lewis acid sites for trapping the anions of Li salt to facilitate the enhancement of t Li + (Figure S17, Supporting Information). [52] For the VA-CPE, the specific surface area of rods is higher than that of the solid silica particles in SS-CPE, consequently improving the value of t Li + of the VA-CPE. Based on these characteristics, VA-CPE expected to enhance the electrochemical performance of LMBs owing to their improved electrolyte wettability, ionic conductivity, and Li + transference number.…”

A Highly Efficient Additive for Direct Reactivation of Waste LiFePO4 with Practical Electrochemical Performance

“…The smaller particle size can enhance the surface area of the material and improve the transmission rates of ions and electrons. , Surface coating is a protective film coated on the surface of LiFePO 4 particles, which can reduce the primary contact between the particles and the electrolyte, preventing oxidization and structural damage to the material and thus improving the electrochemical performance. , Alloying modification can enhance the electrochemical performance of LiFePO 4 by alloying it with other metal elements. For example, alloying with metals such as copper and aluminum can improve the conductivity and ion diffusion rate of the material. , Structural optimization is to optimize the ion diffusion path and electron transport channel by changing the crystal structure of LiFePO 4 or doping other elements, to enhance the electrochemical performance of the material . Adhesive improvement can effectively fix the material and provide a stable structure through improved bonding performance and mechanical strength .…”

“…For example, alloying with metals such as copper and aluminum can improve the conductivity and ion diffusion rate of the material. 18,19 Structural optimization is to optimize the ion diffusion path and electron transport channel by changing the crystal structure of LiFePO 4 or doping other elements, to enhance the electrochemical performance of the material. 20 Adhesive improvement can effectively fix the material and provide a stable structure through improved bonding performance and mechanical strength.…”