TY - JOUR
AU - Jinpeng Wu
AU - Zengqing Zhuo
AU - Xiaohui Rong
AU - Kehua Dai
AU - Zachary Lebens-Higgins
AU - Shawn Sallis
AU - Feng Pan
AU - Louis F. J Piper
AU - Gao Liu
AU - Yi- De Chuang
AU - Zahid Hussain
AU - Qinghao Li
AU - Rong Zeng
AU - Zhi-xun Shen
AU - Wanli Yang
AB - <p><span>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 Na</span><span>0.6</span><span>[Li</span><span>0.2</span><span>Mn</span><span>0.8</span><span>]O</span><span>2</span><span>&nbsp;and compare it with Na</span><span>2/3</span><span>[Mg</span><span>1/3</span><span>Mn</span><span>2/3</span><span>]O</span><span>2</span><span>. Both systems display strong lattice OR activities but with distinct electrochemical stability. The comparison shows that the substantial capacity drop in Na</span><span>0.6</span><span>[Li</span><span>0.2</span><span>Mn</span><span>0.8</span><span>]O</span><span>2</span><span>&nbsp;stems from non-lattice oxygen oxidations, and its voltage decay from an increasing Mn redox contribution upon cycling, contrasting those in Na</span><span>2/3</span><span>[Mg</span><span>1/3</span><span>Mn</span><span>2/3</span><span>]O</span><span>2</span><span>. 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.</span></p>
BT - Science Advances
DA - 02/2020
DO - 10.1126/sciadv.aaw3871
IS - 6
LA - eng
N2 - <p><span>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 Na</span><span>0.6</span><span>[Li</span><span>0.2</span><span>Mn</span><span>0.8</span><span>]O</span><span>2</span><span>&nbsp;and compare it with Na</span><span>2/3</span><span>[Mg</span><span>1/3</span><span>Mn</span><span>2/3</span><span>]O</span><span>2</span><span>. Both systems display strong lattice OR activities but with distinct electrochemical stability. The comparison shows that the substantial capacity drop in Na</span><span>0.6</span><span>[Li</span><span>0.2</span><span>Mn</span><span>0.8</span><span>]O</span><span>2</span><span>&nbsp;stems from non-lattice oxygen oxidations, and its voltage decay from an increasing Mn redox contribution upon cycling, contrasting those in Na</span><span>2/3</span><span>[Mg</span><span>1/3</span><span>Mn</span><span>2/3</span><span>]O</span><span>2</span><span>. 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.</span></p>
PY - 2020
EP - eaaw3871
ST - Sci. Adv.
T2 - Science Advances
TI - Dissociate lattice oxygen redox reactions from capacity and voltage drops of battery electrodes
VL - 6
ER -