Cobalt Cerium Compound Conductive Additive for Alkaline Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cobalt oxyhydroxide-based electronic conductive additives in alkaline secondary batteries suffer from reduced electric conductivity during over-discharge and reverse charging, leading to ineffective performance due to reduction and dissolution in the electrolyte solution, and previous attempts to address this with additional materials have limited evaluation and unsatisfactory results.
Innovation Solution
Incorporating cerium into cobalt compounds to form cobalt cerium compounds with specific crystal structures and ratios, which exhibit high reduction resistance and low specific resistance, enhancing their performance as electronic conductive additives by maintaining conductivity and stability during battery operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cobalt oxyhydroxide is used as an electronic conductive additive, then electric conductivity is improved, but reduction resistance deteriorates during over-discharge and reverse charging
Solution Approach 1:
The invention uses a composite material consisting of cobalt oxyhydroxide combined with at least one element from the group consisting of aluminum, magnesium, and gallium. This composite structure allows the material to maintain high electric conductivity while the added elements provide resistance against reduction during over-discharge and reverse charging, thus resolving the contradiction between conductivity and reduction resistance.
Solution Approach 2:
The invention changes the chemical composition parameters of the conductive additive by incorporating specific elements (aluminum, magnesium, or gallium) in controlled amounts. This parameter modification enhances the stability of cobalt oxyhydroxide against reduction while preserving its conductive properties, addressing both the conductivity and reduction resistance requirements.
2Reliability
If cobalt oxyhydroxide is used to improve electric conductivity, then conductivity is enhanced, but dissolution into electrolyte solution increases
Solution Approach 1:
By forming a composite material with aluminum, magnesium, or gallium, the invention creates a more stable structure that resists dissolution into the electrolyte solution. The additional elements form a protective matrix around the cobalt oxyhydroxide particles, reducing their direct contact and interaction with the electrolyte, thereby minimizing dissolution while maintaining conductivity.
Solution Approach 2:
The chemical composition parameters are modified by adding specific elements that alter the solubility characteristics of the conductive additive. These elements reduce the tendency of cobalt oxyhydroxide to dissolve in the electrolyte while preserving its electronic conductive properties, thus addressing both conductivity enhancement and dissolution prevention.
3Stability of the object's composition
If additional materials are added to cobalt compound to improve stability, then reduction resistance is enhanced, but evaluation data is limited and characteristics are uncertain
Solution Approach 1:
The invention systematically varies the composition parameters by testing different elements (aluminum, magnesium, gallium) and their ratios with cobalt oxyhydroxide. This structured parameter exploration provides comprehensive evaluation data for each added element, enabling precise determination of which combinations optimize reduction resistance while maintaining conductivity, thus resolving the lack of sufficient evaluation data.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The cobalt cerium compounds demonstrate improved reduction resistance and conductivity, maintaining battery performance even during over-discharge and reverse charging, with specific ratios of cerium dioxide and cobalt oxyhydroxide phases optimizing the additive's functionality and reducing internal resistance.
Implementation Method 1
the cobalt cerium compound contains a cobalt oxyhydroxide phase... and a cerium dioxide phase... wherein an abundance ratio of the cerium dioxide phase is 6.5% by mass or more and 88% by mass or less
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A compound having a high reduction resistance and being capable of sufficiently performing a function as an electronic conductive additive when added to a positive electrode active material as an electronic conductive additive is provided. In a method for producing a cobalt cerium compound including a step of depositing a hydroxide containing cobalt and cerium in an aqueous solution containing cobalt ions and cerium ions by changing the pH of the aqueous solution and thereafter performing a treatment of oxidizing the hydroxide, the ratio of the cerium ions contained in the aqueous solution containing the cobalt ions and the cerium ions is set to be more than 5% by atom and 70% by atom or less with respect to the sum of the cobalt ions and the cerium ions before the hydroxide is deposited.