Quartz crystal microbalance(QCM) and linear sweep voltammetry were empolyed to perform in situ mass and charge measurement on Li/V_6O_13(NS) and Zn/V_6O_13(NS) cells. At low Li and Zn compositions in V_6O_13, the simple metal ion intercalation/release process was observed. But at high Li and Zn compositions, secondary processes(morphology change and other complexities), in addition to simple metal ion insertion, were involved during intercalation process and morphology change occurred during deintercalation process. Early faradaic capacity loss of the cell was largely due to the secondary processes.