Investigations of a number of alternative negative electrode materials for use in lithium cells

Abstract

Abstract. There is a considerable interest in the replacement of graphite as the negative electrode reactant in rechargeable lithium batteries by composite electrodes containing alloys or convertible oxides. Some such materials can have much higher theoretical specific capacities than graphite, more than a factor of ten in some cases. In addition it would be desirable to eliminate the irreversible loss of capacity during the first charging cycle that is characterisitic of graphite electrodes, as well to raise the operating potential somewhat in order to reduce the danger of the formation of elemental lithium during recharging.The several strategies that have been followed in the search for attractive alternatives will be briefly described. It has been found to be difficult to obtain the desired combination of high capacity, low first cycle loss and capacity retention upon cycling.Investigations of the electrochemical behaviour of elemental boron and borides (B4C , CAB6, LaB 6, A1B2, SiB3), elemental silicon and silicides (Mg2Si, FeSi2, CoSi~, NiSi2, TiSi2, VSi2) and of siliconmonoxide, SiO, will be reported. The galvanostatic cycling method was used, with thick layer electrodes (30/.tm) deposited upon copper foil in coffee bag-type cells with a liquid electrolyte. Lithium foil was used for the counter and reference electrodes. The results of the investigation of the morphological changes upon cycling, as observed by the use of SEM, will also be presented.

Synthesis and Comparative Investigation of Silicon Transition Metal Silicide Composite Anodes for Lithium Ion Batteries

“…The electrochemical behavior of different silicides, among others FeSi 2 , CoSi 2 , TiSi 2 , and NiSi 2 , was investigated in 2001 by Netz et al in Li metal cells and they reported that TiSi 2 does not react with Li, whereas FeSi 2 and CoSi 2 show very low capacities below 60 mAh · g –1 , whereas the capacity of NiSi 2 is higher with 200 mAh · g –1 . In contrast to that, Fleischauer et al reported that CoSi 2 is inactive towards lithiation when investigating TM‐Si thin films …”

“…While most of the transition metal (TM) silicides, like FeSi 2 , CoSi 2 , TiSi 2 , or NiSi 2 have been reported to have no or only a minor reversible capacity at room temperature and are considered as “inactive”, other metal silicides e.g. Mg 2 Si react reversibly with Li and are, thus, considered “active” …”

Lithiation and Delithiation Reactions of Binary Silicide Electrodes in an Ionic Liquid Electrolyte as Novel Anodes for Lithium‐Ion Batteries

“…Lithiation and delithiation properties of silicides have not yet been investigated in ionic liquid electrolytes. On the other hand, in organic electrolytes, some groups have reported the charge‐discharge properties of some silicides . However, the groups have performed insufficient characterization: they characterized prepared samples by only X‐ray diffraction (XRD), which detects the crystalline material but cannot detect amorphous ones.…”

“…On the other hand, in organic electrolytes, some groups have reported the charge-discharge properties of some silicides. [23][24][25][26] However, the groups have performed insufficient characterization: they characterized prepared samples by only X-ray diffraction (XRD), which detects the crystalline material but cannot detect amorphous ones. Assuming that the synthesized samples include amorphous Si (a-Si), an estimated reversible capacity should largely differ.…”

Gadolinium silicide/silicon composite with excellent high-rate performance as lithium-ion battery anode

“…A forming alloy of Si and transition metal elements is one of some approaches to solve the problem. Many researchers have synthesized various anodes based on transition metal silicides, Mg2Si [4], CaSi2 [5,6], TiSi2 [7], VSi2 [8], CrSi2 [9], FeSi2 [8,10,11], CoSi2 [5,12], NiSi2 [5,8,13], and MoSi2 [9]. Since Mg and Ca are Li-active elements, Mg2Si and CaSi2 showed relatively high capacities at the first cycles.…”