An experimental set-up was designed for measuring the self-field losses of Bi2223/Ag HTS tapes using a transport current method. Ti/Mn_(0.8-x)Sn_xIr_0.2O₂ ternary oxide electrode materials were obtained by Pechini sol-gel method. The organizational structure and electrochemical performance of Ti/Mn_(0.8-x)Sn_xIr_0.2O₂ electrodeswas investigated by Scanning electron microscope (SEM), X ray diffraction (XRD), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that: SnO₂ has a great influence on the organization structure of coating. With the content of SnO₂ increasing, affirmative structure of Mn₃O₄ phase in Ti/Mn _(0.8-x) Sn_xIr_0.2O₂ electrodes oxide coating is gradually reduced, but affirmative structure of SnO₂ phase increased. Compared with the Mn-Ir-based binary oxides, the addition of SnO₂ can significantly improve the current response of electrodes in the range of 0~0.5V and enhance activity of manganese oxide, but suppress activity of iridium oxide. Impedance analysis indicated that the charge transfer resistance,the relaxation time constant and the capacity of different frequency response of electrode materials were changed after addition of SnO₂. In contrast, the Ti/Ir_0.2Mn_0.6Sn_0.2O₂ electrode with better capacitance response and higher activity in the low frequency range (≤ 1Hz), demonstrates the highest specific capacitance.