(Invited) Electrochemically Active Materials: Meeting the High-Energy Density Challenge

Abstract

Energy storage is at a vantage state serving as the primary engine critical for an energy independent global economy currently still very much dependent on tapping into the earth’s natural reserves aided by natural oil and gas exports. The Li-ion battery chemistry has evolved over the years and is at the forefront of secondary rechargeable battery systems, witnessing burgeoning and ever-increasing research activity ever since Sony commercialized the first Li-ion battery in 1990. There have been since then transformative advances in all areas of cathodes, anodes, and electrolytes. Despite much progress, however, lithiated transition metal oxides and carbon remain the preferred typical systems that have made it into the commercial systems currently deployed in the hitherto electric vehicles (EVs). The intense research for identifying higher energy density systems has drawn the attention of Li-air and Li-S systems, of late. The Li-S systems are of particular interest due to the promise of achieving 500 Wh kg-1, a major milestone in meeting the energy density needed for next generation EVs matching and exceeding the performance metrics of the internal combustion engine (ICE).This presentation will discuss the materials challenges that need to be overcome in generating high-energy density cathodes and anodes as well as electrolyte additives to reach the grand challenge of 500 Whkg-1. Research efforts made in the areas of developing cost-effective and scalable new sulfur confinement systems with ability to confine high sulfur loadings of 4-6 mg/cm2 enabling trapping the pernicious polysulfide species combined with unique functional electrocatalysts aided by theoretical first principles calculations exhibiting the propensity to catalyze the formation of Li2S will be discussed. In tandem, progress made in generating new dendrite-free anodes and low-density current collectors exhibiting areal capacities as high as 15 mAh/cm2 with stable cycling over 100 cycles as well as electrolyte additives matching the cathode performance will be outlined.