Secondary Battery Anode Electrolyte Composition for Low Polarization
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Solution Overview
Problem
Lithium-ion batteries face challenges with increased internal polarization due to limited lithium ion migration speed, affecting rate and cycling performance, especially at higher charge rates.
Innovation Solution
Incorporating a solid electrolyte material containing aluminum, titanium, and phosphorus into the negative electrode, which generates Li2O, Li0.5TiO2, and Li3PO4 during cycling, acting as electron/ion conductors to enhance ionic conductance and reduce impedance, while minimizing side reactions with the electrolyte solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the charge rate is increased, then the power output is improved, but the internal polarization increases and cycling performance deteriorates
Solution Approach 1:
The patent applies local quality by introducing a solid electrolyte material specifically at the negative electrode interface where lithium ion migration occurs. This localized modification creates a region with enhanced ionic conductance exactly where it is needed to address the polarization problem during high-rate charging, without altering the overall battery structure or other components.
Solution Approach 2:
The patent employs composite materials by combining the solid electrolyte material (containing aluminum, titanium, and phosphorus) with the negative electrode active material. This composite structure generates multiple conductive products (Li2O, Li0.5TiO2, Li3P, Li3PO4) that work synergistically to enhance ionic conductance and reduce polarization, enabling both high power output and good cycling performance.
2Speed
If the ionic conductance of the negative electrode is enhanced, then the rate performance is improved, but the electronic conductance may be affected
Solution Approach 1:
The patent applies parameter changes by carefully controlling the composition ratios of aluminum, titanium, and phosphorus in the solid electrolyte material, as well as the mass percentages of the resulting conductive products. This precise parameter optimization ensures that ionic conductance is enhanced while electronic conductance remains balanced, achieving both fast lithium ion migration and stable electrical performance.
3Object-affected harmful factors
If the solid electrolyte material is added to the negative electrode, then the impedance is reduced, but the contact between negative electrode active material and electrolyte solution increases
Solution Approach 1:
The patent applies the intermediary principle by introducing the solid electrolyte material as a mediating substance between the negative electrode active material and the liquid electrolyte solution. This intermediary layer reduces direct contact and harmful side reactions while simultaneously providing pathways for efficient lithium ion transport, thus reducing impedance without increasing detrimental interactions.
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 improves the rate and cycling performance of lithium-ion batteries by enhancing ionic conductance, reducing impedance, and minimizing side reactions, leading to better lithium precipitation performance and extended battery life.
Implementation Method 1
the solid electrolyte material is capable of reacting in situ to generate products Li2O, Li0.5TiO2, Li3P, and Li3PO4
Implementation Method 2
as electron/ion conductors, Li2O, Li0.5TiO2, Li3P, and Li3PO4 can enhance the ionic conductance of the negative electrode
Implementation Method 3
the solid electrolyte material added can reduce contact between the negative electrode active material and the electrolyte solution, thereby reducing side reactions
Data Source
AI summary
A secondary battery includes a positive electrode, a negative electrode, and an electrolyte solution; wherein the negative electrode includes a negative electrode material layer. The negative electrode material layer includes a negative electrode active material and a solid electrolyte material. The solid electrolyte material contains aluminum, titanium, phosphorus. The secondary battery is cycled at an ambient temperature of 25° C., and after going N cycles, the negative electrode material layer comprises Li2O, Li0.5TiO2, Li3P, and Li3PO4, wherein 10≤N≤2000. Based on a mass of the negative electrode material layer, a mass percentage of Li2O is 0.006% to 1.25%, a mass percentage of Li0.5TiO2 is 0.005% to 2%, a mass percentage of Li3P is 0.003% to 0.8%, and a mass percentage of Li3PO4 is 0.006% to 1.6%.