Bipolar pulse current charge method for inhibiting the formation of lithium dendrite

A bipolar pulse current charge method was developed to charge lithium metal electrode in 1 mol . L-1 LiPF6 / ethylene carbonate (EC):dimethyl carbonate (DMC) (1:1, V/V) electrolyte. The surface variations of lithium electrode during charge processes were investigated by in situ optical microscopic observation and impedance measurement. It was observed that lithium dendrites formed on lithium electrode during direct current (DC) charge process, but it was inhibited by bipolar pulse charge method. The results of the impedance measurement show that the surface area increases much slower in bipolar pulse current charge process than that in DC charge process. This technique may be useful for the rechargeable lithium battery.