Figure compares the GCD profiles of the two cathodes. The voltages at which discharge plateaus appear agree with the CV results, including the small semi-plateau centering at 2.70 V, which is observed from KFe60. Besides a smaller voltage separation of discharge and charge plateaus, KFeRT delivered discharge and charge capacities of 128.8 and 136.1 mAh g -1 , respectively, at 25 mA g -1 , being much higher than those of KFe60 (88.0 and 89.2 mAh g -1 ).