Electrochemical insertion of lithium in thecation-deficient mixed spinel oxide Mn2.15Co0.37O4

Abstract

Abstract Abstract. Electrochemical properties of a cation-deficient mixed spinel oxide Mn 2.15 Co 0.37 O 4 are investigated. Potentiometric, voltammetric and ac impedance experiments are performed to provide thermodynamic and kinetic data on the lithium insertion reaction vs x in the Li x Mn 2.15 Co 0.37 O 4 system operating below 3 V with one single step. While no evidence for significant structural change is found and in spite of numerous cation vacancies, the Li diffusivity is found to be relatively low (10 −10 to 10 −12 cm 2 s −1 ) over a wide range of Li composition. In terms of cycling performance (4–2 V, C/6 rate), a specific capacity of 45 Ah kg −1 is found over 40 cycles, which is very close to that reported for the 3 V manganese spinel oxide.