Si has been investigated as a promising alternative to conventional graphite because of its high specific capacity and wide operating voltage;... Show moreSi has been investigated as a promising alternative to conventional graphite because of its high specific capacity and wide operating voltage; however, technical challenges related to volume change in the silicon anode have hampered their practical application. In this work, the effects of silicon volume change on electrochemical performance has been studied in NMC532/Si full cells. First, different area specific capacity ratios of the negative to positive electrode (N:P ratio) were investigated using three-electrode cells. With individual electrode potentials monitored by a reference electrode, different depths of lithiation/delithiation at the anode and cathode were found to play an important role on cell performance; the cell with higher N:P ratio displays superior electrochemical performance due to its smaller silicon volume change. Further, calendar-life aging and cycle-life aging of NMC532/Si cells were compared with their electrode potentials monitored using a reference electrode. The observation of larger capacity decay and impedance growth of cycle-life aging cells illustrates the important effect of silicon volume change; significant capacity decay of calendar-life aged cell was observed as well, revealing an essential role of chemical effect of ongoing side reactions at Si anode. Specially-designed silicon with different protocols and electrolyte additives were investigated to address the intrinsic challenges of Si anodes for lithium-ion batteries. Show less
