Alkaline Battery Cathode Composition for Energy Density and Shelf Life
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Solution Overview
Problem
Alkaline batteries face challenges in achieving high volumetric energy density and ambient shelf life due to the limitations of traditional cathode active materials, which often result in reduced performance and stability.
Innovation Solution
The development of non-stoichiometric alkali metal oxides, synthesized through acid treatment of stoichiometric oxides, increases the oxidation state of transition metals, leading to higher energy density and improved stability by incorporating these treated oxides into the cathode of alkaline batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional cathode active materials are used in alkaline batteries, then the battery structure is simple and easy to manufacture, but the volumetric energy density is limited and ambient shelf life is reduced
Solution Approach 1:
The patent applies parameter changes by treating the cathode active material with acid to alter its chemical composition and oxidation state. Specifically, the acid treatment increases the oxidation state of transition metals (e.g., Mn³⁺ to Mn⁴⁺) and modifies the stoichiometry of the metal oxide, thereby enhancing both volumetric energy density and ambient shelf life without fundamentally changing the battery structure
Solution Approach 2:
The patent employs composite materials by creating a treated cathode active material that combines metal oxide with specific crystal structures and oxidation states. The acid treatment process produces a composite structure with enhanced properties, such as combining high oxidation state transition metals with stable crystal lattices, resulting in materials that simultaneously achieve high energy density and improved stability
2Quantity of substance
If the oxidation state of transition metals is increased to enhance energy density, then the crystal structure stability may be compromised, but the patent achieves both high energy density and stability
Solution Approach 1:
The acid treatment process carefully controls parameter changes to achieve the desired oxidation state increase while maintaining crystal structure stability. By adjusting acid concentration, treatment time, and temperature, the patent optimizes the balance between increasing oxidation state (for higher energy density) and preserving the crystal lattice integrity
Solution Approach 2:
The acid treatment acts as an intermediary process that mediates between the desired high oxidation state and crystal structure stability. The acid selectively oxidizes transition metals while the controlled conditions prevent excessive structural degradation, serving as a bridge to achieve both high energy density and structural stability
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 use of acid-treated non-stoichiometric metal oxides enhances the volumetric energy density and ambient shelf life of alkaline batteries, providing improved discharge performance and stability by maintaining the crystal structure and reducing solubility in alkaline electrolytes.
Implementation Method 1
treating an oxide including at least one transition metal and an alkali metal with an aqueous acid solution, including contacting the oxide with the aqueous acid solution (e.g., to remove alkali metal from the oxide and to increase the oxidation state of the transition metal)
Implementation Method 2
The non-stoichiometric metal oxide can be synthesized by acid treatment of a stoichiometric alkali metal oxide to remove alkali metal and to increase the oxidation state of the metal (e.g., a transition metal). The non-stoichiometric metal oxides can provide a battery with a high volumetric energy density.
Implementation Method 3
The non-stoichiometric metal oxide can have low solubility (e.g., less than 300 ppm, less than 100 ppm, or less than 50 ppm) depending on the transition metal in the cathode active material. As a result, battery 10 can have good ambient shelf life.
Data Source
AI summary
A primary battery includes a cathode having a non-stoichiometric metal oxide including transition metals Ni, Mn, Co, or a combination of metal atoms, an alkali metal, and hydrogen; an anode; a separator between the cathode and the anode; and an alkaline electrolyte.