(Invited) Drx and Drx+ As Earth-Abundant Inexpensive Cathodes

Scaling the Li-ion industry to multiple TWh/year will be challenging with NMC-class cathodes because of the cost and resource constraints arising from the use of nickel and/or cobalt. Disordered rocksalt cathodes DRX can be synthesized with almost any transition metal and offer a likely alternative to replace Ni-containing layered cathode materials. Since their invention in 2014 understanding and performance improvement of DRX materials has made significant progress. Materials based on Mn and Ti, which can be synthesized from inexpensive precursors, have shown that specific energies between 650 to 850Wh/kg can be maintained during extended cycling. The ability of these materials to substitute some O by F also provides them with excellent stability even up to high voltage. Since they lose little or no oxygen when highly charged, they are also like to provide high safety. Rate capability, which early on posed a problem for DRX cathodes, has been improved through multiple strategies, and 200mA/g and higher rates can now be achieved without substantial capacity loss. Because these compounds can be synthesized from standard Mn-oxide and Ti-oxide precursors they have the potential to be a low-cost, resource abundant alternative to NMC class materials.