POSITIVE ELECTRODE FOR ALKALI SECONDARY BATTERY, AND ALKALI SECONDARY BATTERY HAVING THE SAME

• Main Authors: TANIMOTO YUYA, IMOTO YUZO, YAMANE TETSUYA, KIHARA MASARU, ASANUMA HIDEYUKI
• Format: Patent
• Language: English; Japanese
• Published: 26.03.2020
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

To provide a positive electrode for an alkali secondary battery, which can suppress the decrease in capacity recovery rate even in the case of being left repeatedly in the state of being bound to a load under a high-temperature environment over a long period, and an alkali secondary battery having the positive electrode.SOLUTION: The battery 2 comprises: an outer can 10; and an electrode group 22 contained together with an alkali electrolytic solution in the outer can 10. The electrode group 22 has a positive electrode 24 which contains a positive electrode base material, and a positive electrode mixture supported by the positive electrode base material. The positive electrode mixture contains a nickel hydroxide, and a positive electrode additive agent. The positive electrode additive agent contains particles of a titanium oxide having an anatase type crystal structure. The titanium oxide particles include primary particles each having an average particle diameter of 5 nm or larger and 10 nm or smaller and a BET specific surface area of 230 m/g or more and 360 m/g or less, and containing niobium of 0.1 mass% or more. The additive rate of the titanium oxide is 0.1 mass% or more and 1.0 mass% or less to an amount of the nickel hydroxide.SELECTED DRAWING: Figure 1 【課題】高温環境下で負荷に繋がれたままの状態で長期間放置されることが繰り返し行われても容量回復率の低下を抑えることができるアルカリ二次電池用の正極及びこの正極を備えたアルカリ二次電池を提供する。【解決手段】電池２は、外装缶１０と、外装缶１０内にアルカリ電解液とともに収容された電極群２２とを備え、電極群２２に含まれる正極２４は、正極基材と、正極基材に担持されている正極合剤と、を備え、正極合剤は、水酸化ニッケルと、正極添加剤と、を含み、正極添加剤は、結晶構造がアナターゼ型である酸化チタンの粒子を含み、この酸化チタンの粒子は、一次粒子の平均粒径が５ｎｍ以上、１０ｎｍ以下であり、ＢＥＴ比表面積が２３０ｍ２／ｇ以上、３６０ｍ２／ｇ以下であり、０．１質量％以上のニオブを含んでおり、酸化チタンの添加率は、水酸化ニッケルに対して、０．１質量％以上、１．０質量％以下である。【選択図】図１