J. Technology and Education, Vol.21, No.1, pp.33-37 (2014)

研究論文

錯体重合法からのリチウム一次電池用二酸化マンガンの合成

 

宮本　信明^＊，  蒲池　悠斗

 

有明工業高等専門学校物質工学科（〒836-8585 大牟田市東萩尾町150番地）

 *miyamoto@ariake-nct.ac.jp

 

Synthesis of Manganese Dioxide by the Polymerized-Complex Method

for Lithium Primary Cells

 

Nobuaki MIYAMOTO^*, and Yuto KAMACHI

 

　 Department of Chemical Science and Engineering, Ariake National College of Technology

（150, Higashihagio-machi，Omuta，Fukuoka  836-8585, Japan）

 

(Received March 26, 2014; Accepted May 1, 2014)

 

Abstract

Polymer gels were formed by the polymerized-complex method using manganese acetate, sodium acetate, citric acid, and ethylene glycol. Sodium manganese composite oxides were prepared from heating gels at 500°C. Manganese dioxides were obtained by the extraction of sodium ions from the composite oxides in nitric acid solution. It was confirmed from XRD patterns that the γ-MnO₂ phase was shown in a low molar ratio (Na/Mn≦0.3) of sodium acetate to manganese acetate in starting materials, and the formation of the α-MnO₂ phase and the γ-MnO₂ phase was observed in a higher ratio. The particle size and specific surface area of the product were 0.1–1.0 μm and 250–270 m²g^-1, respectively. The discharge capacities of the products heated at 375°C as a cathode material in a lithium/　manganese oxide battery were 275–280 mAh g^-1, regardless of Na/Mn ratio. The discharge capacities of the product obtained by this process were higher than those of the product obtained by the sol-gel process using ethanol as a solvent. It was found that the product obtained by this process holds promise for use as a cathode material.

 

Key Words : Sol-Gel Process，Polymerized-Complex Method, Manganese Dioxide，Lithium Primary Cell