Assembled coin cells were studied by cyclic voltammetry at different sweep rates (from 0.2 to 20 mV s -1 ), where the measured current is normalized by the active material mass and the sweep rate, resulting in the unit of A s (V g) -1 , allowing for easier estimation of the stored charge at various sweep rates, and galvanostatic charge/discharge at different specific currents (20 mA g -1 to 10 A g -1 ) between 3 -1 V vs. Li/Li + . Staircase potential-electrochemical impedance spectroscopy (SPEIS) was performed in a frequency range between 1 MHz and 10 mHz in 20 steps, i.e., 100 mV increments between 3 to 1 V vs. Li/Li + , with 10 min chronoamperometric steps between potential increments before each EIS measurement. The impedance was analyzed according to prior work , with the real capacitance being calculated according to equation (1):