MgxMe1-xO1-xH2x Negative Electrode Material for Battery Conversion Reactions
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Solution Overview
Problem
Lithium ion secondary batteries using hydride-based negative electrode active materials for conversion reactions suffer from low charge/discharge efficiency due to high electrochemical polarization, limiting their energy density and cycle stability.
Innovation Solution
A negative electrode active material comprising a compound with a composition formula MgxMe1-xO1-xH2x, where Me is Mn, Fe, Co, Ni, or Cu, and 0.5≤x≤0.9, which is synthesized through a mechanochemical method to enhance stability and reduce electrochemical polarization, thereby improving charge/discharge efficiency and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hydride-based negative electrode active materials are used for conversion reactions, then energy density is improved, but charge/discharge efficiency deteriorates due to high electrochemical polarization
Solution Approach 1:
The invention changes the chemical composition parameters of the negative electrode active material by using a specific compound formula MgxMe1-xO1-xH2x where Me is Mn, Fe, Co, Ni, or Cu and 0.5≤x≤0.9. This parameter optimization reduces electrochemical polarization while maintaining high energy density through conversion reactions, thereby improving charge/discharge efficiency without sacrificing energy density
Solution Approach 2:
The invention employs a composite material approach by combining MgH2 with transition metal oxides (MnO, FeO, CoO, NiO, or CuO) in a specific compositional ratio defined by the parameter x. This composite structure synergistically combines the high capacity of hydrides with the electrochemical stability of transition metal oxides, reducing polarization effects while maintaining high energy density
2Quantity of substance
If conversion reaction materials are used, then capacity is improved, but electrochemical polarization increases reducing efficiency
Solution Approach 1:
The invention optimizes the compositional parameter x in the range 0.5≤x≤0.9 to achieve the right balance between capacity and polarization. By adjusting this parameter, the material maintains high lithium occlusion capacity through conversion reactions while minimizing electrochemical polarization losses, thus improving overall energy efficiency
Solution Approach 2:
The invention introduces local quality variations by incorporating different transition metal elements (Mn, Fe, Co, Ni, Cu) at specific positions in the compound structure MgxMe1-xO1-xH2x. Each transition metal provides local electronic and structural properties that reduce polarization while maintaining high capacity, allowing optimization of local reaction sites for reduced energy loss
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 proposed negative electrode active material achieves high charge/discharge efficiency and increased energy density by minimizing electrochemical polarization and alloy reaction side effects, leading to enhanced battery capacity and reduced thermal damage.
Implementation Method 1
a negative electrode active material occluding and releasing lithium by a conversion reaction has been proposed
Implementation Method 2
synthesized through a mechanochemical method to enhance stability and reduce electrochemical polarization
Data Source
AI summary
A negative electrode active material includes a compound represented by a composition formula of MgxMe1-xO1-xH2x, where Me is at least one selected from the group consisting of Mn, Fe, Co, Ni, and Cu, and 0.5≤x≤0.9.