An Investigation of the Fe-Mn-Si System for Li-Ion Battery Negative Electrodes

Fe-Mn-Si alloys prepared by ball milling were investigated as negative electrodes for Li-ion batteries. X-ray diffraction and room temperature 57Fe Mössbauer measurements were used to characterize alloy structure, which revealed the formation of ternary (Fe,Mn,)11Si19 solid solutions. During cycling in Li cells, the formation of crystalline Li15Si4 was effectively suppressed by inactive transition metal silicide phases, resulting in good cycling performance. In addition, Fe was found to be superior to Mn in avoiding excessive side reactions with electrolyte during cycling.