Positive Electrode Crystal Binder for High-Voltage Battery Stability
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Solution Overview
Problem
Current positive electrode active materials in lithium-ion secondary batteries face challenges with stability and durability during high-potential and high-temperature conditions, leading to reduced cycle performance and capacity.
Innovation Solution
Incorporating a composite compound with crystallinity as a binder and electrolyte in the secondary battery, which can function as a solid electrolyte and prevent direct contact between the active material and the organic electrolyte, thereby enhancing stability and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If positive electrode active materials are exposed to high potential to achieve high capacity, then discharge capacity is improved, but crystal structure stability deteriorates leading to reduced cycle performance
Solution Approach 1:
The patent uses composite oxides with layered rock-salt structure containing multiple transition metals (Co, Ni, Mn, Al) to achieve both high capacity and structural stability. The composite structure allows high potential operation while the synergistic metal combinations maintain crystal integrity during cycling.
Solution Approach 2:
The patent optimizes the local composition and oxidation states of different metal elements within the composite oxide structure. By controlling the distribution and valence states of Co, Ni, Mn, and Al at specific lattice positions, the material achieves high discharge capacity while maintaining local structural stability to prevent degradation.
2Use of energy by moving object
If charge voltage is increased to improve energy density, then energy density is improved, but crystal structure stability deteriorates causing significant deterioration in charge and discharge cycles
Solution Approach 1:
The layered rock-salt composite oxide structure with multiple transition metals enables operation at high charge voltages while maintaining structural integrity. The composite nature of the material provides both the high voltage capability needed for energy density and the structural robustness required for cycle stability.
Solution Approach 2:
The patent controls the oxidation states and compositional ratios of the metal elements to enable high voltage operation. By adjusting the parameters of metal composition and valence states, the material achieves the necessary voltage window for high energy density while maintaining crystal structure stability throughout charging and discharging cycles.
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 a composite compound with crystallinity as a binder and electrolyte improves the stability and cycle performance of the secondary battery, reducing degradation and maintaining high discharge capacity.
Implementation Method 1
a composite compound with crystallinity which has a function of a binder and an electrolyte
Implementation Method 2
a composite compound with crystallinity which has a function of a binder and an electrolyte
Data Source
AI summary
A secondary battery stable in a high-potential state and/or a high-temperature state is provided. The secondary battery includes a positive electrode and a negative electrode, and one or both of the positive electrode and the negative electrode contain an active material and a composite compound with a crystal structure. The composite compound has a function of a binder. The composite compound can also be used as an electrolyte. The composite compound with a crystal structure has typically a molecular crystal. The composite compound with a crystal structure can be obtained by mixing a first compound and a second compound while heating is performed at higher than or equal to a temperature at which a mixture of the first compound and the second compound is melted.