Redox flow devices are described in which at least one of the positive electrode or negative electrode-active materials is a semi-solid or is a condensed ion-storing electroactive material, and in which at least one of the electrode-active materials is transported to and from an assembly at which the electrochemical reaction occurs, producing electrical energy. The electronic conductivity of the semi-solid is increased by the addition of conductive particle to suspensions and the surface modification of the solid in semi-solids: coating the solid with a more electron conductive coating material to increase the power of the device. High energy density and high power redox flow devices are disclosed.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 This invention was made with government support under Grant Number DE-FC26-05NT42403 awarded by the Department of Energy. The government has certain rights in this invention.