ИСТИНА

Lithium-air battery is considered as one of the most promising electrochemical energy storage system mostly due to its outstanding theoretical specific energy (more than 3.5 kWh/kg of active components). However, they are still very far from practical implementation due to some problems. Unfortunately, cathodes, which are typically carbon materials, show instability upon charge-discharge cycling leading to strong capacity fade. TiC, considered as an alternative material, however, demonstrates strong dependence of electrochemical behavior on surface properties of the electrode. Previous cyclic voltammetry (CV) studies of TiC electrodes have shown that despite reduction current fading upon cycling, voltamperometric response can stabilize in some electrolytes. One of possible reasons for such behavior is formation of TiO2 protective layer, that prevents an electrode from further degradation. We believe, such layer should be uniform and thick enough to exclude TiC reaction with oxygen reduction intermediates but at the same time thin enough to allow the electron transfer. Nevertheless, it has been shown that TiO2 layer formed during potentiodynamic cycling is not uniform and doesn’t possess protective properties. We tried to obtain uniform protective layer by oxygen plasma treatment of the electrodes according to previously reported protocol. While pure TiC electrode shows high current values at first cycles and continuous fading with approach to zero, treated electrodes demonstrate lower reduction currents, which are, however, during cycling. Based on obtained data we propose that proper TiC electrode characteristics could be achieved by electrode surface processing, specifically oxygen plasma treatment.