CV with ferrocene-containing electrolyte was recorded at a sweep rate of 10 mV/s between 2.9 and 3.5 V vs. Li/Li + , 2.4 and 3.2 V vs. LixAu, -0.25 and 0.75 V vs. Ag/Ag + (222) for 6 cycles. The half-wave potential of the Fc/Fc + redox couple was calculated for each cycle, and then the mean and standard deviation were calculated from these statistics.