than the hydroxide and fluoride functional group, creating wider spaces for the accumulation of lithium ions. Furthermore, given that the delaminated EE-MXene flakes showed a slightly larger lateral size in contrast to the HF/HCl-MXene, the multilayer HF/HCl-MXene may possess more defects than that of EE-MXene. This makes the HF/HCl-MXenes more accessible to lithium deposition. All MXenes exhibited good rate capability; the capacity decreased by approximately 60 % when the rate increased from 0.1 to 1 A g -1 . The capacity was then recovered when the rate decreased back to 0.1 A g -1 without any loss of capacity, indicating good rate reversibility (Figure ). The difference in capacity of all MXenes became smaller at high current capacity. This is because the current density is so high that the redox-active components were not able to undergo complete lithiation and delithiation. Therefore, at high current density, the redox contribution becomes less dominant and the electrode exhibits EDL-like behaviour, which is more dependent on the specific surface area.