Abstract This paper is about the motion direction of ions in electrochemical devices. The motion direction of ions in an electrochemical device is important content in senior high school chemistry teaching. There is usually a generalized conclusion in teaching: “The anion in the primary battery moves to the negative electrode, the cation moves to the positive electrode; the anion in the electrolysis cell moves to the anode, the cation moves to the cathode.” But this conclusion has some flaws. We can conduct a comprehensive analysis considering the “electrochemical device” and “liquid-phase mass transfer”. We design experiments to guide students to question and explore, thus improving their chemistry core literacy.