Acidified Metal Oxide Cathodes for Stable High-Capacity Batteries
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Solution Overview
Problem
Existing battery technologies face challenges with acidic species in electrodes and electrolytes, as they can degrade components and lead to electrolyte decomposition, gas generation, and cell failure, while superacidity is too strong for many applications, and there is a need for materials that enhance reactivity and electron mobility without causing deterioration.
Innovation Solution
The development of acidified metal oxide (AMO) nanomaterials with controlled surface acidity, used in battery electrodes and electrolytes, which are not superacidic, allowing for improved capacity, cyclability, and longevity by incorporating acidic species that enhance performance without degrading components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acidic species are incorporated into battery electrodes and electrolytes to enhance reactivity and electron mobility, then capacity and cyclability are improved, but component degradation and electrolyte decomposition occur leading to cell failure
Solution Approach 1:
The patent applies parameter changes by precisely controlling the acidity level of metal oxide nanomaterials to achieve optimal performance. Specifically, the metal oxide surfaces are acidified to have a Hammett function H0 greater than -12, which is less acidic than superacids (H0 ≤ -12) but more acidic than conventional metal oxides. This controlled acidity enhancement improves electron mobility and capacity while preventing the excessive reactivity that causes component degradation and electrolyte decomposition.
2Speed
If superacidic materials are used to maximize reactivity enhancement, then electron mobility is significantly improved, but component deterioration and gas generation increase
Solution Approach 1:
The patent converts the harmful effect of excessive acidity into a beneficial outcome by deliberately acidifying metal oxide surfaces to a controlled level. Instead of using superacids that cause gas generation and component deterioration, the patent acidifies metal oxide nanomaterials to have H0 > -12, which provides sufficient electron mobility enhancement while avoiding the harmful side effects. The acidification process itself is used as the beneficial treatment to achieve optimal performance without the drawbacks of superacidity.
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 AMO materials with controlled surface acidity in batteries results in significant capacity gains, extended cycle life, and improved performance, achieving up to 1000 mAh/g capacity and 100-cycle life extension, while maintaining component stability and preventing gas generation.
Implementation Method 1
The AMOs described include those in the form of a nanomaterial, such as a nanoparticulate form, which may be monodispersed or substantially monodispersed and have particle sizes less than 100 nm, for example. The disclosed AMOs exhibit low pH, such as less than 7 (e.g., between 0 and 7), when suspended in water or resuspended in water after drying, such as at a particular concentration (e.g., 5 wt. %), and further exhibit a Hammett function, H0, that is greater than -12 (i.e., not superacidic), at least on the surface of the AMO.
Implementation Method 2
In photocatalysis, for example, the surface hydroxyl groups are thought to promote electron transfer from the conduction band to chemisorbed oxygen molecules.
Data Source
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AI summary
A battery comprising an acidified metal oxide ("AMO") material, preferably in monodisperse nanoparticulate form 20 nm or less in size, having a pH < 7 when suspended in a 5 wt% aqueous solution and a Hammett function H0 > - 12, at least on its surface.