Dual‐Functional Stacked Polymer Fibers for Stable Lithium Metal Batteries in Carbonate‐Based Electrolytes

Abstract

Lithium (Li) metal has long been thought to be an ideal anode material for high‐energy‐density Li metal batteries (LMBs). Nonetheless, a variety of safety risks and short cycle life due to uncontrollable Li dendrite growth limit its practical application. Here, a novel polymer‐based 3D host composed of stacked polymer fibers (SPF) is purposefully designed using a simple electrospinning method to achieve dual‐functional properties that endow bottom‐up Li filling and morphologically regulate Li metal deposition over the host structure. As a result, the SPF allows for uniform Li‐ion flux in the electrode, leading to densely packed Li deposition and further stable cycling in conventional carbonate‐based electrolytes. Besides, a full cell paired with LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode results in a high‐energy‐density battery with a low negative/positive capacity ratio and a wide operating temperature range. This study presents a rational design for improving the stability and safety of Li metal anodes in conventional carbonate‐based electrolytes for advanced LMBs.

A Fluorinated‐Polyimide‐Based Composite Nanofibrous Separator with Homogenized Pore Size for Wide‐Temperature Lithium Metal Batteries

“…In the charge/discharge process of LMBs, the inherent uneven surface of Li anode would serve as the "hotspot" to induce the Li deposition around the tips with stronger electric fields, thus resulting in the irregular dendrite growth. [15][16][17][18][19][20] These dendrites would inevitably pierce traditional polyolefin separators to cause the direct electronic contact between positive and negative electrodes, [12] resulting in inner short circuit, thermal runaway, and further serious security risks in the batteries. To solve problems mentioned above, all kinds of ways have been applied, consisting of the construction of 3D lithium anode, the optimization of electrolyte, as well as the introduction of functional separators, and artificial solidelectrolyte interface (SEI).…”

3D Host Design Strategies Guiding “Bottom–Up” Lithium Deposition: A Review

“…[30] Generally, 3D current collector hosts can be categorized into five types, for example, metal-based hosts, [31,32] alloy-based hosts, carbon-based hosts, [33][34][35] compos-ite hosts, [36][37][38] and dielectric-based hosts. [39,40] The conventional Cu, Ni-based, and carbon-based current collectors, nevertheless, suffer poor lithiophilicity with Li leading to high energy barrier for Li nucleation. [41] In this regard, decorating lithiophilic materials such as metals (i.e., Au, [42] Ag, [43] Zn, [44] and Mg [45] ) and metal oxides (i.e., ZnO, [39] Al 2 O 3 , [46] and MgO [47] ) among others, on 3D hosts is an effective strategy to improve the affinity between current collector and lithium.…”

A 3D Hierarchical Host with Gradient‐Distributed Dielectric Properties toward Dendrite‐free Lithium Metal Anode

“…), carbonaceousbased (nanosphere, [21,22] nanotubes, [23] fiber, [24][25][26] reduced graphene oxide, [27] carbon foam, [28] , etc. ), and polymer-based structures, [29] have been envisaged as the only way that can concurrently accommodate volume changes with electrode integrity and suppress dendritic Li growth. [30,31] Nevertheless, concentration gradients within the 3D host still lead to inhomogeneous lithium-ion migration due to the sluggish ion diffusion kinetics and prolonged diffusion pathway, which induces preferentially top lithium-deposited trigged by intricate kinetic competition between lithium-ion transport and interfacial reactions.…”