Various studies have observed that, during charging, entropic changes can result in a decrease in the temperature of the cell. The result of the 2 C charge is in agreement with these observations, with Figure showing that during the charging stage, the rate of temperature increase does decrease in the middle of the charge step, and this has been attributed to the entropic absorption of heat as the ratio of ions at the electrodes changes, but the overall increase is dominated by the high C-rate. When the cell is polarised to 4.5 V at the end of the cycle, the excess energy is converted to heat resulting in the spike in temperature that is observed at the end of the charge. Overall, the rate of change varies throughout the charge step due to entropic effects and is greatest when the cell polarises. The temperature profiles are in good agreement with those found in literature using alternative methods for recording temperature. After the completion of the cycle, the cell relaxes to OCV and the cell temperature initially rapidly decreases with heat no longer being produced after the current flow has ceased. The rate of temperature decreases then reduces as the temperature of the cell approaches to close to the ambient room temperature. temperature variation is within the recommended range. The PCM coating modifies the behaviour of the cell during the cooling stage after the cycle has been completed at 11000 seconds. The cells that did not have a coating containing the PCM capsules decrease in temperature rapidly once charging current is ceased as previously described for the uncoated cell. For a cell with a coating containing PCM capsules, after the charge step is finished, an initial decrease in temperature of ca. 1 °C is observed. After this initial decrease, the temperature of the cell stabilises again as the PCM undergoes the reverse phase change from liquid to solid. This process releases the stored latent heat from the PCM heating the cell and maintaining the temperature around the cell. This lasts for approximately 900 seconds (15 minutes) after which, the rate of cooling of the cell returns to normal. The observation of absorbing heat during charging, and that heat then being released in the PCM coating during succeeding rest step is evidence that the phase change is taking place and that the PCM is successfully taking heat up from the cell.