In this paper, the electrochemical performances of the organic radical batteries with polynorbornene derivative radical polymer cathode are evaluated by ionic liquid based electrolyte compared to the aprotic based electrolyte with the same salt. The cell with ionic liquid based electrolyte shows more negative redox potential. The discharge capacities increase dramatically at first, with the initial discharge capacity of 44.5 mAh g(-1) leveling out at around the 40th cycle, with the capacity retention of 71.5 mAh g(-1) at the 100th cycle at room temperature, suggesting there is an electrochemical activation during cycling. The results reveal that ionic liquid solvent plays a paramount role in the electrochemical performances. The rate capability of the cell was poor at room temperature of 25 degrees C. However, the cell shows relatively good rate capability at 55 degrees C, with a capacity retention 20 C/1 C of 80.4%. (C) 2011 The Electrochemical Society. [DOI:10.1149/1.3533360] All rights reserved.