Oxygen deficiency in lithium ion materials

lithium batteriesLittle attention has so far been paid to the oxygen stoichiometry of lithium ion battery materials.In most cases presented in the literature, materials were assumed to be fully oxidised.In the light of recent studies, we showed that this assumption must clearly not be done and that performance may be improved by using careful heat treatments.In the spinel material LiCoM-nO 4-δ , a full oxidisation of the material allowed to eliminate the undesirable 4V plateau.[1] In the theoretically-inactive cathode material Li 2 MnO 3-d , oxygen deficiency was clearly shown to be a factor for the electrochemical activity of the material.[2] In the layered rock-salt material Li 1.93 Mn 0.97 Ni 0.10 O 3-δ , a large increase in capacity was observed in materials prepared using an appropriate quenching technique.[3]Fig. 1: X-ray peak positions vary with temperature and oxygen content of LiCoMnO 4-δ[1]