Examining Effects of Negative to Positive Capacity Ratio in Three-Electrode Lithium-Ion Cells with Layered Oxide Cathode and Si Anode

The negative to positive electrode capacity ratio (n:p) is crucial for lithium-ion cell design because it affects both energy density and long-term performance. In this study, the effect of the n:p ratio on electrochemical performance has been investigated for NMC532/Si cells containing a reference electrode. By monitoring individual electrode potentials, depths of lithiation/delithiation at the anode and cathode could be determined. The superior performance of the higher n:p cell, including greater reversibility, better capacity retention, and lower impedance rise, can be attributed to smaller volume changes in the silicon particles during electrochemical cycling.