Electronic Supplementary Information for High-Charge Capacity Polymer Electrodes Comprising Alkali Lignin from the Kraft Process Samuel Leguizamon, Kryssia P. Díaz-Orellana, Julian Velez, Mark C. Thies, and Mark E. Roberts* Department of Chemical & Biomolecular Engineering, Clemson University *e-mail: mrober9@clemson.edu Effect of H2SO4 concentration on Electrochemical Performance The influence of H2SO4 concentration on the electrochemical performance of the composite films is shown in figure S1. The films were prepared using a 10mL solution of 15.3 M AA, 0.124 g of AL, and 69 μL of pyrrole monomer. After polymerization, the film was rinsed and inserted into H2SO4 with a specific concentration: 1 M, 0.5 M, 0.1 M, 0.01 M, 0.001 M, and 0.0001 M. The film was left in the electrolyte solution for 5 min before testing. Cyclic voltammetry shows than higher H2SO4 concentrations lead to sharper redox peaks and decreased peak separation, as expected for a proton-dependent process (Figure S1 a and b). Figure S1. a) Cyclic voltammetry profiles for PPy/AL (prepared in 15.3M AA) at different H2SO4 concentrations. b) Voltage difference between catholic and anodic peaks on (a) vs the pH. Measurements are carried out in a 3-electrode cell on Pt working electrodes with Ag/AgCl as the reference and Pt mesh as the counter. Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A. This journal is © The Royal Society of Chemistry 2015