Mixed Electrode Moisture Capture for Battery Cycle Life
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Solution Overview
Problem
Nonaqueous electrolyte batteries, such as lithium ion secondary batteries, face issues with moisture-induced deterioration and cycle characteristics due to the use of active materials like lithium nickelate, which react with moisture, leading to impurity generation and reduced battery performance.
Innovation Solution
A mixed electrode is developed with a first active material having a smaller specific surface area and an organic moisture capture agent present in an organic binder, where the second active material with a larger specific surface area reacts more easily with water, allowing for selective distribution of the moisture capture agent around the more reactive material, thereby suppressing water reactions and improving battery cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If zeolite is mixed in the electrode active material layer to capture moisture, then moisture absorption capability is improved, but charge transfer is interrupted due to the insulating nature of zeolite
Solution Approach 1:
The patent introduces an organic binder as an intermediary substance that facilitates charge transfer between active material particles while providing a matrix for moisture capture agents. The organic binder conducts charges between particles, mediating the interaction between moisture capture functionality and electrical conductivity requirements.
Solution Approach 2:
The patent changes the physical and chemical parameters of the electrode structure by incorporating organic moisture capture agents with specific properties (organic functional groups, appropriate molecular weight) that differ from conventional inorganic desiccants. This allows tuning of both moisture capture efficiency and electrical conductivity parameters.
2Power
If lithium nickelate is used as active material to improve battery performance, then electrochemical activity is improved, but resistance to moisture deterioration worsens
Solution Approach 1:
The patent applies local quality protection by placing organic moisture capture agents specifically in contact with lithium nickelate particles. The capture agents are distributed throughout the electrode matrix, creating localized protective zones around moisture-sensitive active material particles without affecting the overall electrochemical performance.
Solution Approach 2:
The patent implements preliminary anti-action by incorporating moisture capture agents into the electrode structure before battery assembly and operation. These agents proactively capture moisture molecules before they can reach and react with lithium nickelate, preventing deterioration in advance.
3Object-affected harmful factors
If inorganic moisture capture agents are used in the electrode, then moisture capture efficiency is improved, but electrical conductivity deteriorates
Solution Approach 1:
The patent fundamentally changes the parameter of moisture capture agent material type from inorganic to organic. This parameter change enables simultaneous achievement of moisture capture functionality and electrical conductivity, as organic materials can be selected with appropriate conductive properties and functional groups for moisture binding.
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
This approach effectively enhances the storability and cycle characteristics of the battery by minimizing the adverse effects of moisture on the active materials, reducing impurity generation, and maintaining efficient charge transfer within the electrode.
Implementation Method 1
an organic moisture capture agent that is present in the organic binder
Implementation Method 2
an organic binder that binds the first active material and the second active material
Data Source
AI summary
A mixed electrode for a nonaqueous electrolyte battery includes: a first active material; a second active material that reacts with water more easily than the first active material; an organic moisture capture agent; and an organic binder that binds the first active material and the second active material. The organic moisture capture agent is present in the organic binder and the first active material has a smaller specific surface area than the second active material. Thus, the storability of the mixed electrode is improved and when the mixed electrode is applied to the battery, the cycle characteristics of the battery are improved.