| Manganese dioxide is a complex compound, which can be expressed as the form of MnOx(x≤2). The crystal structure of this material has many types, such as (,(,(, etc. Owing to the structure difference of crystal cells, the electrochemical activity of various crystal types is also greatly different. Among all the crystal types, (-MnO2 has the highest activity because it possesses single and double chains intergrowth of each other. In addition to application in battery system as electrode material, (-MnO2 can also be used as electrocatalyst in zinc-air cells, since it has obviously electrocatalytic activity for oxygen electrochemical reduction. Conventionally, the electrochemical researches of manganese oxide were carried out in aqueous electrolyte environment. Recently, the research of all solid-state battery system is becoming one of the hot topics in the battery area. To study (-MnO2 and its characteristics as a whole in the solid-state battery system has become the need of manganese battery.This thesis consists of four parts. The first one aims to survey the fundamental electrochemical reaction mechanism, characteristics of MnO2 as an electrode material, and the principles of Zn/MnO2 battery system, to introduce one of the parts of all solid-state alkaline Zn/MnO2 battery— polymer gel electrolyte. At the same time, as an electrocatalyst for oxygen reduction in zinc-air battery, the basic reaction mechanism and research progress of this material are also introduced.The second part express the preparation and electrochemical characterization of MnO2 nanowires. Using electrolysis manganese dioxide as the raw material, MnO2 nanowire is prepared easily from ammonia or distilled water by hydrothermal method. By means of the electrochemical measurements, the effects of anodic ions (NH4+, H+) on the electrochemical properties of as-prepared MnO2 nanowire were discussed in detail.The third chapter shows the application of the (-MnO2 in all solid-state Zn/MnO2 battery. This chapter is divided into two parts.1. All solid-state Zn/MnO2 primary battery. In this part, PVA-KOH-H2O solid-state electrolyte was prepared by using solvent-casting method. The ion conductivity of this electrolyte is 10-3s/cm at room temperature. It also has high electrochemical stability, as to stainless steel and nickel electrode, the stable voltage windows is 2.0V and 3.0V, respectively. All solid-state Zn/MnO2 battery was fabricated successfully and its performance was examined. This Zn/MnO2 battery system showed good discharge performance and 213mAh/g of discharge capacity was achieved at 1mA.2. All solid-state Zn/MnO2 rechargeable battery. A solid-state polymer electrolyte consisting of PVA, KOH, ZnO and H2O was prepared according to the above-mentioned method. The conductivity and electrochemical stability of this electrolyte can meet the demand of battery. The battery exhibited certain discharge-charge cyclic ability between defined voltage ranges. After 30 charge-discharge cycles, discharge capacity retains at 54.96% of the initial discharge capacity at 5mA. The forth chapter concerns the application of MnO2 in zinc-air battery. This chapter consists of three parts.1. Nanostructured MnO2/mesocarbon microbeads (MCMB) composite has been prepared successfully by using K2S2O8 to oxidize MnSO4·H2O and used in zinc-air cell as electrocatalyst for oxygen reaction. The as-prepared electrocatalyst has a special micro-morphology and crystal structure, which can provide more opportunities for oxygen reduction on air electrode. The catalytic activity of this catalyst for oxygen reduction is higher than that of normal (-MnO2. A solid-state zinc-air battery system, using as-prepared MnO2/MCMB as electrocatalyst, exhibits excellent discharge characteristic and shows 1.4Ah of discharge capacity at 62.8mA. 2. A new air electrode by a combination use of dual functional Ag / MnO2 catalysts based on single-walled carbon nanotubes (SWNTs) was developed successfully by chemical reducing silver permanganate with hydrazine. The electr...
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