Suppressing lithium dendrite formation using electrolyte additives

EZEQUIEL P. M. LEIVA; FRANCISCO GARCÍA SORIANO; DANIEL BARRACO; MARÍA DEL CARMEN ROJAS; MANUEL OTERO; GUILLERMINA LUQUE; MARÍA BELÉN SUAREZ RAMANZIN; ANDREA CALDERÓN; FABIANA OLIVA

Durban

Conferencia; 70 th Annual Meeting of the International Society of Electrochemistry (ISE).; 2019

International Society of Electrochemistry

Currently, Lithium batteries present the most promising solution for energy storage in many applications, from electronic devices to electrical vehicles and electrical network power storage. In recent years, to meet the technology developments and the human?s living standards, the rechargeable batteries, are regarded as increasingly appealing alternatives to be applied in both grid electrical energy storage and electrical vehicles. Lithium-sulfur (Li-S) battery is widely researched due to its higher theoretical specific capacity and theoretical energy density in comparison with lithium-ion battery. The lithium anode is absolutely necessary for lithium-sulfur battery, which plays an important role for the electrochemical stability and the security of the battery. Lithium metal is regarded as a preferred electrode material for the anode of lithium-sulfur battery, which is mainly attributed to its excellent performances such as low gravimetric density (0.59 g cm−3), high theoretical specific capacity (3860 mAh g−1) and fine negative redox potential (−3.040 V vs. standard hydrogen electrode). So the lithium metal plays a indispensable role for the next generation high-performance energy storage systems The working mechanism for Li anode is Li+ plating/stripping from the anode instead of intercalation/de-intercalation in graphite anode during charge/discharge process. During the repeated charge-discharge cycling, the continuous uneven deposition and stripping of lithium induce uncontrollable growth of lithium dendrites, which not only breaks solid electrolyte interfacial (SEI) film and leads to the generation of ?dead Li? with low Coulombic efficiency (CE), but also induces safety hazards (like internal short circuit, combustion/explosion of full cells) since it can penetrate through the polymer separator and form micro-short circuits between the positive and negative electrodes, causing the serious safety issues including fire and even explosions. The aim of the present work is to avoid formation of lithium dendrites by adding additives in the electrolyte. The electrolyte was based on LiTFSI 0.5 M and LiNO3 0.25M in 1,2-dimethoxyethane(DME)/1,3-dioxolane (DOL) 1:1 with different additives. The electrochemical behavior was studied by means of Li/Cu cells and Li/Li cells by charge-discharge cycles at different current rates, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Lithium before and after cycling was also characterized by scanning electron microscopy (SEM).