Positive Electrode Active Material Using Kink Bands for Capacitance Retention
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Solution Overview
Problem
Positive electrode active materials with O2-type, T #2-type, and O6-type structures face issues with capacitance maintenance due to expansion and contraction during charging and discharging, leading to breakage and reduced electron conduction paths, resulting in decreased capacitance over repeated cycles in batteries.
Innovation Solution
A positive electrode active material with specific oxygen 1s X-ray photoelectron spectroscopy characteristics, where no peak exists between 525 eV and 531 eV binding energy or has a peak ratio of 1 or more between 531 eV and 538 eV, and a composition formula with specific element ratios, is used, allowing for kink band formation that prevents conduction path disruption during charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If positive electrode active materials with O2-type, T #2-type, or O6-type structures are used to achieve high discharging/charging capacitance in high potential region, then the initial discharge capacitance is improved, but the capacitance maintenance rate after repeated discharging and charging decreases due to expansion and contraction causing breakage
Solution Approach 1:
The patent applies beforehand cushioning by introducing a solid electrolyte coating layer on the surface of the positive electrode active material particles before battery assembly. This coating layer acts as a protective cushion that accommodates the expansion and contraction of the active material during charge-discharge cycles, preventing particle breakage and maintaining electron conduction paths. The coating layer is applied in advance to prevent damage before it occurs, thereby maintaining high capacitance over repeated cycles while preserving the high initial discharge capacitance of the O2-type, T #2-type, or O6-type structured active materials
2Productivity
If positive electrode active materials undergo expansion and contraction during discharging and charging, then the discharging/charging capacitance is achieved, but breakage occurs at the positive electrode active material cutting electron conduction paths
Solution Approach 1:
The patent applies flexible shells and thin films by using a solid electrolyte coating layer that conforms to the surface of the positive electrode active material particles. This thin film coating is flexible enough to accommodate the volume changes and structural transformations that occur during charge-discharge cycles, allowing the active material to expand and contract without breaking. The coating layer maintains structural integrity while enabling the electrochemical reactions necessary for high discharging/charging capacitance
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 solution results in high initial discharge capacitance and maintained capacitance rate after repeated charging and discharging cycles, enhancing the performance and longevity of batteries.
Implementation Method 1
Positive electrode active materials having at least one type of structure selected from among O2-type structure, T #2-type structure and O6-type structure expand and contract due to discharging and charging
Implementation Method 2
an oxygen 1s X-ray photoelectron spectroscopy spectrum obtained by X-ray photoelectron spectroscopy measurement
Data Source
AI summary
There are provided a positive electrode active material at which an oxygen 1s X-ray photoelectron spectroscopy spectrum obtained by X-ray photoelectron spectroscopy measurement satisfies the following condition 1 or the following condition 2:condition 1: a peak top does not exist in a region in which a binding energy is from 525 eV to less than 531 eV, and a peak top exists in a region in which the binding energy is from 531 eV to 538 eV; orcondition 2: a ratio of discharge photoelectron intensity Ihe at a peak top, which exists in a region in which the binding energy is from 531 eV to 538 eV, with respect to discharge photoelectron intensity Ile at a peak top, which exists in a region in which the binding energy is from 525 eV to less than 531 eV, is 1 or more.