A Review of Composite Lithium Metal Anode for Practical Applications

Abstract

potential (−3.040 V vs standard hydrogen electrode). [8][9][10] Objectively, the energy density of Li batteries should take all parts of a battery into considerations instead of only anode. In order to achieve high-energydensity Li batteries, practical conditions including limited Li (<10 mAh cm −2 ), low negative/positive capacity (N/P) ratio (<3), and lean electrolyte are necessary. [11,12] In addition, fast charge is imperative with the popularization of portable electronics and electrical vehicles. [13] Consequently, high charge current density (>3 mA cm −2 ) is a confronted issue.Nowadays, the practical applications of Li batteries are still hindered by the formation of Li dendrites, rapid pulverizations of Li metal, and volume fluctuation. [14][15][16] Tremendous efforts have been devoted to disclosing the mechanism of Li plating/stripping and developing strategies to regulate its behaviors thus extending the lifespan of Li batteries during the past half century, including electrolyte formulations, [17][18][19][20][21][22][23][24][25][26][27] interfacial modifications, [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] solid-state electrolytes, [45][46][47][48][49][50][51][52][53][54][55] composite anodes, [56][57][58][59][60][61][62][63] and so on. [64] Thereinto, composite Li anode emerges as a promising strategy to regulate Li plating/stripping behaviors and promote the advances of Li batteries.Generally, a composite Li anode is composed of a 3D host and fresh Li metal. The 3D host is endowed with the unique surface chemistry and interconnecting structure. [65] The superiorities contributed by composite Li anode mainly include:(1) improving electronic conductivity, such as decreasing areal current density and avoiding the generation of "dead Li." Conductive hosts with high specific surface area, such as carbon-based and metal-based hosts, can decrease areal current density to prolong the time for depletion of ion at the anode surface to induce dendritic Li according to Sand's time model. [66] Therefore, the formation of Li dendrites will be effectively inhibited at low areal current density and the cyclability can be improved effectively.(2) Homogenizing Li-ion flux over the surface of Li metal. The distribution of Li ions over the surface of Li anode impacts the subsequent Li plating/stripping behaviors significantly. Uniform Li plating/ stripping can be improved by regulating the interactions between lithiophilic sites on 3D host surface, such as polar functional groups, [67,68] and Li ion to homogenize Li-ion flux. [69] (3) Maintaining dimensional stability of anode. 3D hosts can confine plating Li in the inside pores to avoid the Lithium (Li) metal is considered as a promising anode candidate for nextgeneration batteries owing to its extremely high specific capacity and low reduction potential. However, Li metal anode is still hindered by uncontrolled Li dendrites and extreme volume fluctuation. Composite Li metal anode emerges as an attractive strategy to suppress Li dendrites and ...

Fast Li+ Transport of Li−Zn Alloy Protective Layer Enabling Excellent Electrochemical Performance of Li Metal Anode

“…The similar phenomenon has already been reported by many papers. [30] On the contrary, the cycled surface of LiÀ Zn protected Li metal anode is still very flat and compact, and there is no strong signal of the organic electrolyte decomposition. The corresponding crosssectional image illustrates that the interior of the Li electrode is still very dense, suggesting the LiÀ Zn alloy as a buffer layer can physically isolate the bulk Li metal from the liquid electrolyte.…”

Challenges, mitigation strategies and perspectives in development of Li metal anode

“…One potential solution to mitigate this influence is to use an electronically conductive three-dimensional (3D) porous host for Li deposition, which can enhance the effective surface area and reduce the current density. [114] Moreover, the large interfacial fluctuation for planar foils can also be avoided via a 3D host design. The 3D form offers the ability to handle high current density, decrease volume change and strengthen the SEI.…”

“…As a consequence, LAFN demonstrates much stable lithium ion plating/stripping plateaus, and improved CE, compared to Li foil. [114] Copyright © 2016, Springer Nature; B, ref., [115] Copyright © 2018, Springer Nature; C, ref., [116] Copyright © 2016, Springer Nature; D, ref., [117] Copyright © 2019, Springer Nature; E, ref., [118] Copyright © 2020, Springer Nature; E, ref., [119] Copyright © 2017 The Authors…”

Nanostructured Tin-based Alloys Composites using Deep Eutectic Solvents as Electrolytes

“…The SEM analysis, presented in Figure 7, proves the successful electrodeposition of Sn and Sncarbon materials. The incorporation of carbon materials on a metal matrix is of an extreme value since it can lead to the development of new metallic materials with increased properties for electronic and battery applications (Balach et al 2018;Molenda and Molenda 2011;Shi et al 2020).…”