Effect of cathode/anode area ratio on electrochemical performance of lithium-ion batteries

The effects of cathode/anode area ratio on the electrochemical performance of lithium-ion batteries are investigated using 2032-type coin full cells. As the anode area is increased from 1.13 (ø12 mm) to 2.54 cm² (ø18 mm) while maintaining the cathode area as 1.13 cm² (ø12 mm), both coulombic efficiency and discharge capacity at the first formation step become increasingly worse, probably owing to greater formation of solid electrolyte interphase (SEI). Moreover, rate capability also declined with increased anode area, whereas discharge capacity retention behavior during 1C/1C charge/discharge cycling appeared similar except for a slightly decreased capacity of coin cells with larger anode areas. The findings indicate that cathode/anode area ratio should be carefully evaluated to achieve reliable data on electrochemical performance.