Study of Capacity Fade of Lithium-Ion Polymer Rechargeable Batteries with Continuous Cycling

A cycle life study was done on commercial lithium-ion polymer batteries to quantify contributions to capacity fade with continuous charge–discharge cycling. The cell consists of graphite (meso-carbon microbeads) as an anode material and lithium cobalt oxide as a cathode material. Analyses were done using ac impedance spectroscopy, scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The results show that contributions to capacity fade with continuous charge/discharge cycling included solvent–salt deposition on the anode surface; however, instability and cation disorder in the cathode electrode were identified as the main reasons for capacity fade with continuous charge/discharge cycling.