| Polyaniline (PANI) has been considered as a promising conductivity materials, which can be doped into conductive state from insulating state, at the same time both light weight, corrosion resistance, toughness, and low cost characteristics. And can obtain kinds of composites by in-situ polymerization method and improve its solubility in organic solution by organic functional groups. PANI has a special interest in supercapacitors and Li ion batteries electrode materials for this application due to their excellent capacity for energy storage, low cost, easy synthesis, stability, electrochemical reversibility, existence of several oxidation structures, special redox mechanisms.In this study, PANI/AC composite materials were synthesized by in-situ polymerization method using aniline and activated carbon as raw materials in acid condition (acid medium) and a new method is prepared the composites materials PANI/AC and PANI in alkali condition (alkali medium). The surface morphology and crystallite structure of composites were examined by scanning electron microscope (SEM) and the structure of PANI and composites were analyzed by FT-IR. Then use these materials to assemble the two-electrode capacitors in electrolyte of 6 mol/L KOH aqueous solution, Galvanostatic method and AC impedance were used to measure the electrochemical performance of PANI/AC and AC materials. In addition, useing dodecylbenzenesulfonic acid(DBSA) as dopants to prepare a kind of soluble polyaniline, and then PANI/PEO composite was prepared by mechanical mixing method as a new conductivity binder and to assemble Li ion batteries, Galvanostatic method and AC impedance were used to measure the electrochemical performance conductivity binder.(1) In two-electrode capacitor, the best reaction conditions of PANI/AC composite material are An/AC mass ratio for 1:2.5 and An:/APS mole ratio for 1: 0.5, when the concentration of acid is 1 mol/L and the time is 8 hours, using the activated carbon with the specific area for 1659.2m~2/g as raw materies . At a current density of 500mA/g, the PANI/AC electrode exhibits high specific capacitance of 432.10F/g, which is 2.32 times larger than that of the activated carbon electrode's specific capacitance of 186.25F/g in electrolyte of 6mol/L KOH aqueous solution. The specific capacitance retention is 97.10% after 500 charge-discharge cycles in the potential range of 0～0.8V.(2) The IR results shows that the PANI and PANI/AC composite materials that prepared in alkali medium condition with the peak postion and peak similar to that in acid medium, it shows that can be a new means to prepare PANI and PANI/AC composite materials.(3) The PANI prepared in alkali medium has redox behaviors from -0.2v～0.4v, At a current density of 500mA/g, the PANI electrode exhibits specific capacitance of 90.94F/g, The specific capacitance retention is 80.35% after 500 charge-discharge cycles in the potential range of 0～0.8V.(4) The PANI/AC prepared in alkali medium has a pair of redox behaviors from -0.2v~0.4v, At a current density of 500mA/g, PANI/AC electrode exhibits high specific capacitance of 218.75F/g, which is 1.17 times larger than that of the activated carbon electrode's specific capacitance of 186.25F/g. The specific capacitance retention is 99.98% after 500 charge-discharge cycles in the potential range of 0~0.8V.(5) In Li ion batteries, the capacity increase as the PANI quality ratio in PANI/PEO conductivity binder increases and then decrease, reaching 20% can obtain the optimization initial charge and discharge capacity. The result shows the battery with PANI/PEO binder has higher capacity than the PTFE binder's at same condition. PANI/PEO binder battery exhibits high initial charge and discharge capacity of 154.59mAh/g and 138.69mAh/g larger than of the PTFE binder's capacity of 141.80mAh/g and 127.93mAh/g, which capacity are increase 9.02% and 8.41%, and the coulomb efficiency are 89.71% and 90.22%. Both PANI/PEO binder and PTFE have a good cycle performance. |
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