(47a) Delineating and Controlling the Electrode-Electrolyte Interfacial Reactions in High Energy Density Batteries

Rapid increase in global energy use and growing environmental concerns have prompted the development of clean, sustainable, alternative energy technologies. Renewable energy sources like solar and wind are a promising solution, but electrical energy storage (EES) is critical to efficiently utilize electricity produced from renewable sources as they are intermittent. EES is also the only viable near-term option for electrification of transportation sector. Rechargeable batteries are prime candidates for EES, but their widespread adoption for electric vehicles and grid electricity storage requires optimization of cost, cycle life, safety, energy density, power density, and environmental impact, all of which are directly linked to severe component materials challenges and the interfacial reactions between them. This presentation will focus on delineating and controlling the electrode-electrolyte interfacial reactions and consequent crossover of chemical species in high energy density batteries.

With an aim to develop sustainable battery technologies at an affordable cost with high energy density and free from supply chain issues, the presentation will focus on interfacial reactions in two battery systems: (i) lithium-ion batteries with low- or cobalt-free, high-nickel cathodes and graphite or lithium-metal anodes and (ii) lithium-sulfur batteries with sulfur cathode and lithium-metal anode or anode-free cells with Li₂S cathode. The high-nickel cathodes are synthesized with a coprecipitation of transition-metal hydroxide precursors followed by calcining with LiOH under controlled temperature and oxygen flow in order to obtain commercially-relevant particle size and morphologies. Practically-relevant pouch lithium-ion cells or lithium-sulfur cells fabricated with the cathodes and anodes are disassembled and characterized after hundreds or thousands of cycles with advanced characterization techniques, such as X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and high resolution transmission electron microscopy, to track the anode-electrolyte interfacial reactions, cathode-electrolyte interfacial reactions, as well as the crossover of chemical species between the two electrodes through the electrolyte/separator during cycling. Based on the data, the impact of interfacial reactions and crossover of chemical species between the two electrodes on cell performance is established. The understanding gained is utilized to condition the electrode surfaces or modify electrolyte compositions in order to minimize undesirable interfacial reactions and enhance the cycle life of lithium-ion and lithium-sulfur cells.