Cross-linked poly(2,2,6,6-tetramethylpiperidinyl-N-oxyl-4-yl methacrylate) (PTMA) gel used in organic radical batteries (ORBs) is characterized by rheological measurements, and the micro structure of gel-state cathodes is observed using low vacuum SEM. The storage elastic modulus of the cross-linked PTMA gel is under 10 kPa which is in the range of soft gel. It suggests that the PTMA cathodes are fairy flexible in the battery. The ORBs with the cathodes made from cross-linked PTMA/vapor grown carbon fiber (VGCF) composite show excellent discharge rate properties (20C/1C capacity 91%). The structure of needle-like VGCF penetrating PTMA particles in the composite results in excellent rate capabilities. In the PTMA gel cathode, the cross-link structure of the PTMA has the effect of maintaining homogeneous dispersion of VGCF, which gives improvement in cyclability. The capacity and resistance of the ORBs are maintained in the initial state after repetitive bending 250 times. We demonstrate that the gel state cross-linked PTMA is a promising electrode material for practical flexible batteries. (C) 2017 The Electrochemical Society. All rights reserved.