Atomic force microscopy (AFM), conductive atomic force microscopy (CAFM) in air, and scanning electrochemcial microscopy (SECM) in 2 M H2SO4 have been used to investigate model composite electrodes obtained by pressing sieved MnO2 particles into a Pb matrix. These model electrodes shall resemble new composite electrodes produced by coldspraying and currently being tested for Zn electrowinning. CAFM showed a very uneven distribution of the current path through the matrix electrode with the highest currents measured at the MnO2/Pb domain boundary. SECM images in the substrate-generation/tip-collection mode in vertical and horizontal planes could show spatial concentration distribution of H+, O-2 and H2O2 that could be evaluated qualitatively despite interfering turbulent convection due to raising gas bubbles. There is a concentration overvoltage due to deviations of the H+ and O-2 concentration close to the surface from the bulk value. It amounts to about 40-50 mV for both compounds. H2O2 is formed as an intermediate and is consumed at the MnO2 catalyst particles.