Enhanced capacity and lower mean charge voltage of Li-rich cathodes for lithium ion batteries resulting from low-temperature electrochemical activation

High capacity and high energy cathodes prepared from Li-rich 0.35Li(2)MnO(3)center dot 0.65Li[ Mn0.45Ni0.35Co0.20]O-2 materials must be activated in Li-ion cells prior to normal cycling, in order to achieve their high discharge capacity of > 250 mA h g(-1). Activation is performed by charging the electrodes to potentials of 4.7-4.8 V vs. Li/Li+. This communication reports on the discovery that electrochemical activation of these cathode materials at low temperatures (0-15 degrees C) increases their discharge capacity, lowers average charge voltage, and diminishes voltage hysteresis. Work with the above mentioned material is reported as a representative example.