Electrochemical Cycling of Redox-Active Boron Cluster-Based Materials in the Solid State
Austin D. Ready, Ahamed Irshad, Anna Kallistová, Moises Carrillo, Milan Gembický, Ram Seshadri, Sri Narayan, Alexander M. Spokoyny
Abstract
This work demonstrates the first successful electrochemical cycling of a redox-active boron cluster-based material in the solid state. Specifically, we designed and synthesized an ether-functionalized dodecaborate cluster, B 12 (OCH 3 ) 12, which is the smallest redox-active building block in the B 12 (OR) 12 family. This species can reversibly access four oxidation states in solution, ranging from a dianion to a radical cation. We show that a chemically isolated and characterized neutral [B 12 (OCH 3 ) 12 ] 0 cluster can be utilized as a cathode active material in a PEO-based rechargeable all-solid-state cell with a lithium metal anode. The cell exhibits an impressive active material utilization close to 95% at C/20 rate, a high Coulombic efficiency of 96%, and reversibility, with only 4% capacity fade after 16 days of cycling. This work represents a conceptual departure in the development of redox-active components for electrochemical storage and serves as an entry point to a broader class of borane-based materials.