Nanometer alpha-nickel hydroxide and its prepn

Abstract

The present invention provides one kind of nanometer alpha-nickel hydroxide and its preparation process. The preparation process adopts bivalent nickel slat as main material, and includes the steps of: adding doping metal salt to compound reaction solution, compounding precipitant solution with potassium hydroxide or sodium hydroxide, adding the precipitant solution to the reaction solution under stirring and ultrasonic dispersing to obtain nickel hydroxide, washing and drying to constant weight. Thus prepared nanometer alpha-nickel hydroxide has small and homogeneous particle size, great specific surface area, high heat stability, stability in alkali medium, high specific discharge capacity, and other features, and may be used as the positive pole material in secondary alkali ZnNi cell, H-Ni cell and FeNi cell.

Description

technical field [0001] The invention relates to the technical field of chemical power sources, in particular to a nanometer α-nickel hydroxide and a preparation method thereof. Background technique [0002] Traditional alkaline secondary batteries such as Zn / Ni, Cd / Ni, M-H / Ni, Fe / Ni, etc., the positive electrodes are all made of β-nickel hydroxide or compound additives doped with Co, Cd, Mn and other elements. β-nickel hydroxide is made of active material. This nickel electrode material mainly has the following four deficiencies: [0003] First, the uncharged state of the β-nickel hydroxide electrode cannot match the charge of the zinc electrode in the charged state to form a battery that can be discharged immediately, but it needs to be charged and formed separately. Before the battery reaches the best performance, it needs to be carried out for dozens of years. times of charging and discharging. This has just caused huge energy waste and the impr...

AI Technical Summary

Problems solved by technology

This kind of zinc / nickel battery has a large difference in the amount and volume of positive and negative active materials, which also brings certain difficulties to the manufacture of the battery.

Moreover, the mass specific capacity of the battery with the nickel electrode made of β-nickel hydroxide as the positive electrode is also relatively low

[0005] Third, since β-nickel hydroxide is a semiconductor with extremely poor conductivity, the conductivity of the electrode composed of it as an active material is very poor, and the activated electrode active material affects the The discharge performance and discharge efficiency of the electrode itself

At present, the utilization rate of the positive electrode active material of zinc-nickel battery is only 40-60% of the total amount.

[0006] Fourth, the nickel electrode made of β-nickel hydroxide as the active material is easy to cause overcharge during charging and discharging.

This overcharge will cause β-nickel hydroxide to become larger γ-nickel oxyhydroxide instead of β-nickel oxyhydroxide with a similar volume to β-nickel hydroxide when the electrode is electrooxidized, resulting in electrode Volume expansion after overcharging

At the same time, the formation of γ-nickel oxyhydroxide will also cause the "memory effect" of the electrode, and the expansion and "memory effect" of the electrode will directly shorten the cycle life of the battery

[0007] Although people have tried to overcome the above-mentioned shortcomings by preparing α-nickel hydroxide recently, China's invention patent applications No. 00123599.0, 01129615.1, and 01109694.2 disclose a spherical α-nickel hydroxide, a nanometer α-nickel hydroxide and a Nano-phase α-nickel hydroxide and preparation method thereof, but above-mentioned patents all have their own defects, they also have common deficiencies: first, doping elements in the prepared α-nickel hydroxide The content of the impurity element and the amount of doped impurities are difficult to control, because the synthesis process steps and processes are complex, resulting in uncertain types and contents of impurity elements in the actual synthesis process; at the same time, impurities not only reduce the actual capacity of the active material, but also directly reduce the electrode discharge. The specific capacity affects the performance of the battery; secondly, its synthesis process is relatively complicated, which leads to high synthesis cost of active materials and difficulty in industrial production; thirdly, the prepared α-nickel hydroxide is used as the positive electrode active The discharge capacity of the electrode made by the material is low, and the highest specific capacity value is only 59% of the theoretical mass specific capacity (578mAh / g) of the α-nickel hydroxide electrode (see Embodiment 1 of the Chinese invention patent application specification No. 01129615.1); the fourth , the production cost of the battery manufactured by using the α-nickel hydroxide prepared by the above-mentioned patented method as the positive electrode active material is also high, the performance price is relatively low, and the market competitiveness is lacking

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