Dissociate lattice oxygen redox reactions from capacity and voltage drops of battery electrodes

Dissociate lattice oxygen redox reactions from capacity and voltage drops of battery electrodes

TitleDissociate lattice oxygen redox reactions from capacity and voltage drops of battery electrodes
Publication TypeJournal Article
Year of Publication2020
AuthorsJinpeng Wu, Zengqing Zhuo, Xiaohui Rong, Kehua Dai, Zachary Lebens-Higgins, Shawn Sallis, Feng Pan, Louis FJ Piper, Gao Liu, Yi- De Chuang, Zahid Hussain, Qinghao Li, Rong Zeng, Zhi-xun Shen, Wanli Yang
JournalScience Advances
Volume6
Issue6
Paginationeaaw3871
Date Published02/2020
Abstract

The oxygen redox (OR) activity is conventionally considered detrimental to the stability and kinetics of batteries. However, OR reactions are often confused by irreversible oxygen oxidation. Here, based on high-efficiency mapping of resonant inelastic x-ray scattering of both the transition metal and oxygen, we distinguish the lattice OR in Na0.6[Li0.2Mn0.8]O2 and compare it with Na2/3[Mg1/3Mn2/3]O2. Both systems display strong lattice OR activities but with distinct electrochemical stability. The comparison shows that the substantial capacity drop in Na0.6[Li0.2Mn0.8]O2 stems from non-lattice oxygen oxidations, and its voltage decay from an increasing Mn redox contribution upon cycling, contrasting those in Na2/3[Mg1/3Mn2/3]O2. We conclude that lattice OR is not the ringleader of the stability issue. Instead, irreversible oxygen oxidation and the changing cationic reactions lead to the capacity and voltage fade. We argue that lattice OR and other oxygen activities should/could be studied and treated separately to achieve viable OR-based electrodes.

DOI10.1126/sciadv.aaw3871
Short TitleSci. Adv.
Refereed DesignationRefereed