The structural and chemical origin of the oxygen redox activity in layered and cation-disordered Li-excess cathode materials.
Lithium-ion batteries are now reaching the energy density limits set by their electrode materials, requiring new paradigms for Li(+) and electron hosting in solid-state electrodes. Reversible oxygen redox in the solid state in particular has the potential to enable high energy density as it can deliver excess capacity beyond the theoretical transition-metal redox-capacity at a high voltage. Nevertheless, the structural and chemical origin of the process is not understood, preventing the rational design of better cathode materials. Here, we demonstrate how very specific local Li-excess environments around oxygen atoms necessarily lead to labile oxygen electrons that can be more easily extracted and participate in the practical capacity of cathodes. The identification of the local structural components that create oxygen redox sets a new direction for the design of high-energy-density cathode materials.
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.|Department of Materials Science and Engineering, UC Berkeley, Berkeley, California 94720, USA.
Dong-Hwa
DH
Seo
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.|Department of Materials Science and Engineering, UC Berkeley, Berkeley, California 94720, USA.
Jinhyuk
J
Lee
Department of Materials Science and Engineering, UC Berkeley, Berkeley, California 94720, USA.
Alexander
0000-0002-9021-279X
A
Urban
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Rahul
R
Malik
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
ShinYoung
S
Kang
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.|Department of Materials Science and Engineering, UC Berkeley, Berkeley, California 94720, USA.|Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Gerbrand
G
Ceder