Stabilization of insertion electrodes for lithium batteries

This paper discusses the techniques that are being employed to stabilize LiMn2O4 spinel and composite LixMnO2 positive electrodes. The critical role that spinel domains play in stabilizing these electrodes for operation at both 4 V and 3 V is highlighted. The concept of using an intermetallic electrode MM′ where M is an active alloying element and M′ is an inactive element (or elements) is proposed as an alternative negative electrode (to carbon) for lithium-ion cells. An analogy to metal oxide insertion electrodes, such as MnO2, in which Mn is the electrochemically active ion and O is the inactive ion, is made. Performance data are given for the copper–tin electrode system, which includes the intermetallic phases eta-Cu6Sn5 and Li2CuSn.