Core-Shell Battery Particles for Thermal Stability Without Capacity Loss
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Solution Overview
Problem
Lithium secondary batteries face instability and risk of ignition or explosion when exposed to high temperatures due to side reactions between the flammable electrolyte and electrodes, which reduces their thermal stability and capacity retention.
Innovation Solution
A core-shell particle is developed, comprising a porous substrate like zeolite coated with a thermoplastic polymer shell, which absorbs the electrolyte and releases a flame retardant at high temperatures to suppress side reactions, thereby enhancing thermal stability without compromising capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a flammable solvent is used as electrolyte to achieve high energy density, then the battery capacity is improved, but the thermal stability deteriorates when exposed to high temperature
Solution Approach 1:
A core-shell particle is introduced as an intermediary substance between the electrolyte and electrodes. The shell layer acts as a physical barrier preventing direct contact between the electrolyte and electrodes, while the core contains flame retardant that can be released under high temperature conditions. This mediator approach allows the battery to maintain high energy density with flammable electrolyte while adding thermal protection functionality.
Solution Approach 2:
The invention changes the physical and chemical parameters of the electrolyte system by adding core-shell particles. The particles modify the electrolyte's thermal properties through the flame retardant release mechanism, transforming the electrolyte from highly flammable to thermally stable while maintaining its electrochemical performance characteristics.
2Reliability
If flame retardant is added to suppress side reactions at high temperature, then thermal stability is improved, but capacity retention rate deteriorates
Solution Approach 1:
The flame retardant is pre-loaded within the core of the core-shell particle, enclosed by the shell layer. Under normal operating conditions, the shell prevents the flame retardant from interacting with the electrolyte, preserving battery capacity. When high temperature is detected, the shell decomposes and releases the flame retardant in advance to suppress thermal runaway, thus achieving both capacity retention and thermal stability.
Solution Approach 2:
The flame retardant is localized within the core region of the particle, separated from the bulk electrolyte by the shell layer. This local concentration strategy ensures that the flame retardant only activates where needed (at the particle-electrolyte interface under high temperature), minimizing its impact on overall battery capacity while providing effective thermal protection.
3Reliability
If porous substrate is used to adsorb electrolyte to suppress side reactions, then thermal stability is improved, but capacity retention rate deteriorates due to electrolyte adsorption
Solution Approach 1:
The shell layer acts as a flexible barrier that controls the interaction between the porous substrate and electrolyte. Under normal conditions, the intact shell prevents electrolyte adsorption onto the porous substrate, maintaining capacity retention. Under high temperature conditions, the shell becomes permeable or decomposes, allowing the porous substrate to adsorb electrolyte and suppress side reactions, thus achieving thermal stability without permanent capacity 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 core-shell particle effectively prevents ignition and explosion by absorbing the electrolyte and releasing a flame retardant at high temperatures, maintaining the battery's capacity retention and thermal stability.
Implementation Method 1
the porous substrate included in the core adsorbs the electrolyte, thereby suppressing side reactions between the electrode and the electrolyte
Implementation Method 2
the shell is decomposed when the secondary battery is exposed to a high-temperature environment, and the porous substrate included in the core adsorbs the electrolyte
Data Source
Figure 1
AI summary
The present disclosure provides a core-shell particle including a core including a porous substrate and a flame retardant, and a shell including a thermoplastic polymer and covering the core, and a secondary battery, a module, and a device including the same.