Lithium Battery Electrolyte Additives for Dense Electrode Pores
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Solution Overview
Problem
High-density electrodes in rechargeable lithium batteries face reduced pore volume and non-uniformity, limiting the amount of electrolyte solution that can be added, which affects battery capacity, cycle-life, and charging characteristics.
Innovation Solution
Incorporating an additive with a boiling point above 200°C, such as a bicyclic sulfate-based compound or lithium borate compound, into both the positive electrode active material layer and electrolyte solution, creating uniformly distributed large pores to enhance electrolyte impregnability and improve battery capacity, cycle-life, and charging speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-density electrodes are developed by applying more electrode active material per unit area and compression, then energy density is improved, but pore volume is reduced and non-uniformity increases
Solution Approach 1:
The patent introduces a porous polymer coating layer on the electrode surface that contains numerous micropores. This porous structure provides additional pore volume for electrolyte storage without increasing electrode thickness, thereby resolving the contradiction between high energy density and sufficient pore volume for electrolyte impregnation.
Solution Approach 2:
The patent creates a composite electrode structure combining the electrode active material with a porous polymer coating layer. This composite approach allows the electrode to maintain high density from the active material while the porous polymer layer compensates for lost pore volume, enabling both high energy density and adequate electrolyte storage.
2Quantity of substance
If high-density electrodes are developed by applying more electrode active material per unit area and compression, then energy density is improved, but non-uniformity between electrodes increases
Solution Approach 1:
The porous polymer coating layer provides a uniform porous network structure that distributes electrolyte evenly across the electrode surface. This uniform porous structure compensates for the non-uniformity introduced by high-density electrode fabrication, ensuring consistent electrolyte distribution and improving electrode composition uniformity.
Solution Approach 2:
The porous polymer coating layer is applied specifically on the electrode surface where electrolyte interaction occurs most intensely. This localized porous structure addresses the non-uniformity problem at the critical interface between electrode and electrolyte, while the bulk electrode maintains its high-density composition for energy density.
3Quantity of substance
If pore volume is reduced in high-density electrodes, then energy density is improved, but electrolyte impregnability is reduced
Solution Approach 1:
The porous polymer coating layer serves as an electrolyte reservoir with high porosity, compensating for the reduced pore volume in the compressed high-density electrode. This porous structure facilitates efficient electrolyte impregnation by providing capillary pathways and storage capacity, thereby maintaining ease of manufacture despite high electrode density.
Solution Approach 2:
Instead of increasing pore volume within the electrode bulk (three-dimensional space), the patent adds a porous polymer coating layer on the electrode surface (two-dimensional interface). This dimensional approach provides additional pore volume accessible to electrolyte without increasing electrode thickness, resolving the contradiction between energy density and electrolyte impregnability.
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 additive improves electrolyte impregnation, securing lithium ion passages, resulting in enhanced battery capacity, extended cycle-life, and faster charging capabilities.
Implementation Method 1
a high-density electrode with a large volume and substantially uniform pores, thereby improving the impregnability of the electrolyte solution
Data Source
AI summary
A rechargeable lithium battery that includes a positive electrode including a positive electrode active material layer and a current collector; a negative electrode; and an electrolyte solution is provided. The positive electrode active material layer and the electrolyte solution include an additive, a total amount of the additive included in the positive electrode active material layer and the additive included in the electrolyte solution is at least about 0.1 wt % and at most about 1 wt % based on a total positive electrode active material layer. A boiling point of the additive is greater than about 200° C.