Study On The Nickel Oxide And Manganese Oxide As The Cathode Materials For Rechargeable Alkaline Batteries

The present dissertation comprehensively reports the systematical studies on the improvement of alkaline batteries. The first study is on the dope modification of NaBiO₃ to discharge and cycling properties of MnO₂．Solid phase synthesis was used to prepare NaBiO₃ In order to increase the purity and decrease the cost, we use the freshly prepared Bi(OH)₃ to react with NaClO, obtaining highly pure NaBiO₃．The synthesis, preparation and characterization were studied. Further experiment shows that nano-NaBiO₃ could be prepared by the reaction of the acidified Bi(NO₃) ₃ of suitable concentration with NaClO-NaOH. XRD, TEM, TG-DSC and FT-IR were used to characterize the structure and properties of NaBiO₃ product.By doping with the above highly pure NaBiO₃ to MnO₂, the effect of this new type doping agent on the structure, electrochemical property and cycling properties of MnO₂ electrode was examined. Results show that NaBiO₃ can obviously improve the electrochemical and cycling properties for both electrolytic MnO₂ and chemical MnO₂．The dope mechanism is also discussed. Based on the lab tests, we cooperated with a famous battery plant to carry out a pilot test and fabricate a batch of doped alkaline batteries. The appraise test result shows that under a constant current of 1000mA, the discharge time of the doped battery is 37．1%, higher than that of the alkaline batteries which are specially used for digital products.Mn₃O₄ has been known to be an electrochemical inert substance which is formed during charge/discharge. Its formation is the root reason of cycling capacity decay. The present paper proposes a solving method by means of doping NaBiO₃ to Mn₃O₄．Result shows that the Mn₃O₄ doped with NaBiO₃ not only has good cycling property but still has a cycling capacity of 261mAh g^-1 at high current density of 500mA g^-1 , and the discharge time is reduced to 30'14".With development of digital products, alkaline Zn-Ni batteries spring out. Their specific capacity is several times as high as alkaline Mn batteries at high discharge current. However, in the alkaline Zn-Ni cells, NiOOH is the cathode material which has high redox potential and bad wet stability, so it is hard to synthesize highly pure NiOOH by chemical oxidation in one step. The present dissertation develops a new way to prepare the NiOOH of high specific capacity by making use of NaClO-NaOH mix solution. Furthermore, we have prepared nano bar shape NiOOH through effective controlling the crack of spherical NiOOH. FSEM, XRD, TEM, TG-DSC, FT-IR, XPS and galvanostatic charge-discharge were employed to examine the micro structure and electrochemical property. At the same time, we developed the recovery treatment of the waste solution of NiOOH preparation process. Using the above NiOOH material as cathodes, we examined the electrochemical characteristics of spherical shape and nano NiOOH with galvanostatic charge-discharge and cyclic voltammetry. Result shows spherical shape NiOOH has good discharge property and bar shape NiOOH has good super high speed charge /discharge property. We cooperated with a famous battery plant and fabricated two batches of AA alkaline batteries and their temperature dependence and storage property were examined. The inspection test shows that at a constant discharge current of 1000 mA, their discharge time is as high as 62．1 min, far higher than 7．2 min of the general alkaline Mn batteries, very suitable for digital products. Additionally, the alkaline Zn-Ni batteries are rechargeable to a certain extent. That makes higher ratio of property / price.To pursue secondary battery cathode material of super high speed and high capacity has been our target. Based on the synthesis of NaBiO₃ and NiOOH, we explored the synthetic method of nano AgO. The result reveals that AgO electrode has ideal super high speed charge/discharge property, thus being able to reduce the charge time down to 2'50". Besides, an inspection method of fast charge/discharge property was developed through mathematical imitation.Finally, the present dissertation studies a new alkaline secondary battery. We used the less expensive halogen as the cathode material of alkaline secondary battery, thus avoiding using the Ni and Mn which are getting rarer and rarer. The halogen battery has a discharge voltage as high as 1．9 V and a specific energy of 90-110Wh kg^-1 as well as an ideal circulation property.