Abstract: To provide a carbon electrode material that is capable of decreasing cell resistance during initial charging and discharging to improve battery energy efficiency. A carbon electrode material for a negative electrode of a manganese/titanium-based redox flow battery including carbon fibers (A), carbon particles (B) other than graphite particles, and a carbon material (C) for binding the carbon fibers (A) and the carbon particles (B) other than graphite particles and satisfying (1) a particle diameter of the carbon particles (B), (2) Lc(B), (3) Lc(C)/Lc(A), (4) A mesopore specific surface area, and (5) a number of oxygen atoms bound to the surface of the carbon electrode material.

Abstract: To provide a carbon electrode material which is capable of decreasing cell resistance during initial charging and discharging while improving oxidation resistance to Mn ions. A carbon electrode material for a redox flow battery, including carbon fibers (A), graphite particles (B), and a carbon material (C) for binding the carbon fibers (A) and the graphite particles (B), the carbon electrode material satisfying (1) Lc(C), (2) Lc(C)/Lc(A), (3) an average curvature of the carbon fibers (A), and (4) a number of oxygen atoms bound to a surface of the carbon electrode material.