Correlating hysteresis and voltage fade in lithium- and manganese-rich layered transition-metal oxide electrodes

Electrochemical studies demonstrate a strong correlation between the phenomena of hysteresis and voltage fade in lithium- and manganese-rich layered transition-metal oxide electrodes. A mechanism is proposed that entails both the reversible and irreversible migration of transition metal ions. Their reversible migration to a metastable configuration, suggested to involve the occupation of tetrahedral sites in the lithium layer, is manifested as a 1 V hysteresis in site energy for 10-15% of the lithium content. The irreversible migration of the transition metal ions through the metastable 'hysteresis' sites to localized and lower energy cubic environments results in the observed voltage fade phenomenon. (c) 2013 Elsevier B.V. All rights reserved.