The present disclosure relates to porous electrodes, membrane-electrode assemblies, electrode assemblies and electrochemical cells and liquid flow batteries produced therefrom. The disclosure further provides methods of making electrodes, membrane-electrode assemblies and electrode assemblies. The porous electrodes include polymer, e.g. non-electrically conductive polymer particulate fiber, and an electrically conductive carbon particulate. The non-electrically conductive, polymer particulate fibers may be in the form of a first porous substrate, wherein the first porous substrate is at least one of a woven or nonwoven paper, felt, mat and cloth. Membrane-electrode assemblies and electrode assemblies may be produced from the porous electrodes of the present disclosure. Electrochemical cells and liquid flow batteries may be produced from the porous electrodes, membrane-electrode assemblies and electrode assemblies of the present disclosure.