Lithiophilic Nanowire Architectures as Hosts for Lithium Metal Anodes

Abstract

Lithium (Li) metal is considered the ‘holy grail’ of battery anodes and has attracted enormous interest due to its low density (0.59 g cm-3), high theoretical capacity (3860 mAh g-1) and lowest electrochemical potential (-3.07 V vs. standard hydrogen electrode - SHE) [1-2]. However, several issues during its cycling in a Li-metal battery (LMB) have hindered its commercialization. Some notable problems include the formation of an unstable solid electrolyte interphase (SEI), excessive dendrite growth and subsequent short-circuiting during the Li stripping/plating process [3-4].In our poster presentation, we will detail the design of a hierarchical nanowire (NW) – Carbon paper (CP) host for dendrite-free and stable cycling in LMBs. These NWs were grown on high surface area carbon paper substrate via a modified Vapour-Liquid-Solid (VLS) approach. The lithiophilic NWs enabled quick Li infusion (< 10 sec) in the NW-CP substrate whereas no Li infusion was possible in lithiophobic bare CP substrate (without the presence of NWs). Additionally, the NW morphology helped in reducing the localized current density on the surface of the NW-CP host, thereby promoting uniform Li deposition during plating/stripping process. With careful design of the NW-CP host, symmetric cell performance with high current density (3 mA cm-2) and areal capacity (3 mAh cm-2) was achieved for up to 500 h while a typical Li metal anode failed within 200 h. High loading NMC811 and high specific capacity Sulfur (S) cathodes demonstrated superior performance using NW-CP host as compared to pristine Li anodes.In addition, we will also present some new concepts of NW decorated lithiophilic interlayers, which can be integrated with pristine Li metal anodes for uniform Li deposition. These lithiophilic interlayers can promote ‘bottom-up’ Li infilling between the Li-interlayer interface such that dendrite formation near the separator and eventual short-circuit is avoided. Detailed electrochemical as well as density functional theory (DFT) analysis shedding light on the improved lithiophilic properties of NW use in stabilizing Li metal anodes will also be presented. Overall, our work is aimed to develop high energy density (ED) Li metal anodes to meet the rising ED demands of electric vehicle (EV) industry.