A Research On Factors That Influence The Performance Of Lithium-polyaniline Secondary Battery

Polyaniline(PANi) is a novel conductive polymer, it has many advantages, such as: wide range of sources of saw materials, a simple synthesis process, low cost and good environmental stability, excellent electrochemical properties and so on. Polyaniline’s application and study on cathode materials of lithium secondary battery has became more and more hot in recent years. In this paper polyaniline/carbon is used as cathode materials of lithium secondary battery, and the synthesis of polyaniline, reduction reaction of polyanline, removing of small molecules of polyaniline, battery electrolyte, the assembly process of battery, the battery charging and discharging system are mainly studied. mainwhile the performance of lithium-polyaniline secondary battery is assessed well by impedance spectroscopy and charge-discharge tests.To prepare polyaniline/carbon composite materials through the method of adsorption and double oxidants, under certain objective conditions to control the reaction temperature, the lower temperature, the better performance of battery with polyaniline/carbon as cathode materials. Using hydrazine hydrate as reductant and reacting for 12 hours at 40 ℃, emeraldinebase can be completely converted to reduced state polyaniline, and the degree of reduction of this material is 93.8% by XPS test. Compared to emeraldinebase, the diffraction peak of C=C and C=N of quinone structural unit of reduced state polyaniline weaken significantly in the infrared spectrum. It is found that the crystallinity of reduced state polyaniline is higher than emeraldinebase by XRD test, and reduced state polyaniline has more microscopic linear and pore structure than emeraldinebas e from the high-powered SEM image.By studying how electrolyte influence the performance of lithium-polyaniline secondary battery, it is found that when the concentration of lithium ion is 1.55 mol/L, the capacity of battery is highest. And when the additive amount of vinylene carbonate into electrolyte is 2%, the cycle performance of battery is best. There are a variety of combinations of diaphragm, when using 2 layers of glass fiber membranes, the battery has the highest capacity, and when using 1 layer of glass fiber membranes compound with 1 layer of polypropylene membrane, the battery has the best cycle performance. For lithium- polyaniline button cell,when the quality of polyaniline on cathode is 12.5 mg, the battery has higher capacity and better cycl e performance. There two ways to prepare cathode sheet: coating method and tableting method, the battery has a higher capacity but poor cycle performance when in the former way. Different charging and discharging system influence the performance of battery greatly, the higher charge cut-off voltage, the greater capacity of battery, but the poorer cycle performance(when voltage exceeds 3.9 V). The larger charge-discharge rate, the lower capacity of battery, but the charge-discharge rate has little impact on the cycle performance of battery.Finally, by analyzing the current market situation of lithium secondary battery and competitive advantages of lithium-polyaniline secondary battery, come to the conclusion: lithium-polyaniline secondary battery has a brode space for development and immeasurable markert prospect.