August 1, 2016.
Lithium-ion (Li-ion) batteries are commonly used in portable electronics such as cellphones and laptops. Most Li-ion batteries operate on intercalation principle with typical theoretical specific energy of 400-600 (Wh/Kg). There is great scientific interest in lithium-sulfur (Li-S) batteries as a possible successor of traditional Li-ion batteries because Li-S holds the potential of being a very powerful (1550 Wh/kg theoretical specific energy) yet very cost-efficient battery (due the abundance and inexpensiveness of sulfur). However, one major problem in Li-S battery research is the polysulfide “shuttle phenomenon”, which is the shuttling of polysulfide species due to the dissolution of sulfide from the cathode. This is a parasitic reaction upon the anode and results in corrosion and ultimate inactivity of the battery. To overcome this challenge we have studied the electrolyte design formulation to gain further insight of possible solvent types which can inhibit the dissolution of sulfides. Computational modeling based on density functional theory (DFT) is used in the bonding energy analysis of sulfide solvate structures. The solvate structures studied in this research are Li2Sx (x=4,6,8) interacting with dimethoxyethane (DME), 1,3-dioxolane (DOL), and a mixture of both. Li-S battery performance can be subsequently improved by rational electrolyte design from understanding of solvate structure.
Materials Chemistry | Numerical Analysis and Scientific Computing
Pacific Northwest National Laboratory (PNNL)
*This project has been made possible with support from Chevron (www.chevron.com) and the California State University STEM Teacher Researcher Program.