NEW POLY(2,5-DIMERCAPTAO-1,3,4-THIADIAZOLE) AND POLY(ANILINE) CO-INTERCALATED V_2O_5 NANOCOMPOSITE MATERIALS FOR RECHARGEABLE LITHIUM BATTERY

摘要

New organic/inorganic nanocomposite materials are synthesized by co-intercalation of poly(2,5-dimercapto-l,3,4-thiadiazole) and poly(aniline) into V_2O_5 xerogel and characterized in connection with their application to rechargeable lithium battery. FTIR confirms that the 2,5-dimercapto-1,3,4-thiadiazole (DMcT) and aniline (ANI) after reacting with a V_2O_5 xerogel are polymerized. Intercalation expands the V_2O_5 lattice by 4.8 A, indicating co-existence of monolayer of PDMcT and PANI in the interlayer of V_2O_5. X-ray absorption near-edge structure (XANES) spectroscopic analysis shows the reduction of vanadium ion from +5 to +4.8 state by intercalation. The electrochemical cells with the synthesized materials as positive electrode are discharged and charged between 4 - 2 V under constant current density of 0.5 mA/cm~2. For the PDMcT-intercalated V_2O_5, discharge capacitiy of the as-prepared sample is slightly lower than that of unintercalated V_2O_5, while a significant improvement is observed after oxygen treatment, which suggests post oxygen treatment plays an important role in activating PDMcT as an electrochemical active species for lithium insertion. In case of the PDMcT and PANI co-intercalated samples, oxygen treatment might have a strong influence on PANI not on PDMcT. Cyclability is found to be improved either by oxygen treatment on PDMcT/V_2O_5 or further intercalation of PANI into PDMcT/V_2O_5.