Birnessite Cathode Stabilized by Bismuth and Copper Ions
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Solution Overview
Problem
Lithium-ion batteries face safety and economic issues due to thermal runaway reactions caused by cobalt in cathode materials, leading to underutilization of high energy density capabilities in applications like electric vehicles and grid-scale storage.
Innovation Solution
A stabilized birnessite cathode material is developed using bismuth and copper ions, which maintains structural integrity during lithium intercalation, enhancing charge transfer characteristics and allowing for high energy density in rechargeable Li-ion batteries, and achieving close to theoretical energy densities in primary batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cobalt is used in cathode materials to achieve high energy density, then energy storage capability is improved, but safety deteriorates due to thermal runaway reactions
Solution Approach 1:
The patent extracts cobalt from the cathode material composition and replaces it with manganese-based birnessite. This removal of the harmful cobalt element eliminates the source of thermal runaway reactions while maintaining the battery's energy storage functionality through the manganese oxide cathode structure.
Solution Approach 2:
The patent changes the chemical composition parameters of the cathode material by substituting cobalt with manganese and optimizing the oxidation states (Mn3+/Mn4+ ratio). This parameter change transforms the material properties to achieve both high energy density and improved safety by preventing thermal runaway.
2Use of energy by moving object
If cobalt is used in cathode materials to achieve high energy density, then energy storage capability is improved, but manufacturing cost worsens
Solution Approach 1:
The patent extracts cobalt, the expensive element, from the cathode material and replaces it with manganese, which is abundant and cost-effective. This extraction of the costly component directly reduces manufacturing costs while maintaining energy storage performance through the manganese-based cathode structure.
Solution Approach 2:
The patent employs manganese oxide, a cheap and abundant material, as the cathode active substance. This substitution with a low-cost material reduces the overall manufacturing cost of the battery while achieving the required energy density for practical applications.
3Reliability
If manganese is used to replace cobalt for improving safety and reducing cost, then safety and economics are improved, but energy density capability deteriorates due to thermal instability
Solution Approach 1:
The patent creates a composite cathode material consisting of birnessite structure with controlled Mn3+/Mn4+ ratios and specific crystallographic features. This composite structure combines the safety advantages of manganese with enhanced stability and energy density characteristics, achieving a balance between safety and performance.
Solution Approach 2:
The patent optimizes the oxidation state parameters (Mn3+/Mn4+ ratio) and structural parameters of the manganese oxide to enhance its electrochemical performance. By controlling these parameters, the material achieves both improved safety and high energy density, overcoming the inherent limitations of simple manganese oxides.
4Reliability
If manganese oxide cathode is used for safety improvement, then safety is improved, but structural stability deteriorates during lithium intercalation
Solution Approach 1:
The patent develops a composite birnessite structure with specific layered arrangements and controlled compositional ratios. This composite structure provides structural robustness during lithium intercalation while maintaining the safety advantages of manganese-based materials, preventing both thermal runaway and structural degradation.
Solution Approach 2:
The patent performs preliminary structural optimization of the manganese oxide cathode by controlling synthesis conditions to achieve specific birnessite structures with enhanced stability. This preliminary structuring ensures that the cathode maintains its integrity during subsequent lithium intercalation cycles, preventing structural collapse.
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 stabilized birnessite cathode enables significant retention of theoretical capacity and high energy efficiency in Li-ion batteries, making them suitable for rechargeable applications and achieving near-theoretical energy densities in primary batteries, while also improving safety and reducing costs by replacing cobalt with manganese.
Implementation Method 1
the composition being stabilized by bismuth and copper ions
Implementation Method 2
maintains structural integrity during lithium intercalation
Implementation Method 3
The method further comprises stabilizing the cathode with the bismuth and copper ions during the discharging and charging
Data Source
AI summary
A battery comprises a housing, an electrolyte disposed in the housing, an anode disposed in the housing, a stabilized cathode disposed in the housing and comprising a cathode material. The cathode material comprises a composition selected from birnessite or layered-polymorph of manganese dioxide (δ-MnO2), the composition being stabilized by bismuth and copper ions, a conductive carbon, and a binder. The anode can be at least 50% (m/m) lithium, magnesium, aluminum, or zinc.