https://doi.org/10.1351/goldbook.P04407
When a single electrochemical reaction occurs at an electrode (i.e. all other electrochemical reactions may be neglected): \[I=I_{\text{a}}+I_{\text{c}}\] where \(I\) is the total current, \(I_{\text{a}}\) is the positive partial anodic current and \(I_{\text{c}}\) is the negative partial cathodic current. When more than one reaction is significant the reactions may be numbered and the numbers used as subscripts: \(I_{\text{1,a}}\), \(I_{\text{1,c}}\), \(I_{\text{2,a}}\), etc. Then: \[I=\sum I_{i,\text{a}}+\sum I_{i,\text{c}}\]