Two Phenanthrenequinone-Based Compound Cathode Materials for Lithium Ion Batteries

Two phenanthrenequinone (PQ)-based compounds 2,7-dinitro-9,10-phenanthrenequinone (DNPQ) and 2,7-diamino-9,10-phenanthrenequinone (DAPQ) were prepared by introducing a strong electron-withdrawing nitro group or an electron-donating amino group at 2,7-positions of PQ. CR2430 coin-type cells were assembled using these compounds as cathode active materials and lithium metal as an anode. For comparison, the electrochemical performance of pristine PQ under the same condition was tested. The initial discharge specific capacity of DNPQ is 221 mAh g−1 which is higher than pristine PQ and PAPQ, because the nitro group is electrochemically active and can reversibly insert/deinsert lithium. Due to the lower solubility in the electrolyte, PNPQ has better cycling stability than PQ. This study shows that the introduction of nitro group in phenanthrenequinone can increase its specific capacity and cycle stability.