Functionalized Matrix Additives for High Voltage Battery Stability
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Solution Overview
Problem
Conventional electrolytes in lithium-ion batteries are unstable at high voltages and temperatures, leading to decomposition, gas generation, acidic product formation, and safety concerns, which limits the cycle life and energy density of high-energy batteries needed for applications like electric vehicles.
Innovation Solution
The use of a liquid electrolyte formulation including a lithium salt, non-aqueous solvent, and a functionalized matrix additive, such as a polymer or silica-based material, which forms a stable solid electrolyte interphase and scavenges undesirable components like acids and transition metal ions, improving high voltage and high temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used in lithium-ion batteries, then the batteries can operate at standard voltages and temperatures, but the electrolytes decompose at high voltages above 4.2V and high temperatures, leading to shortened cycle life and safety concerns
Solution Approach 1:
The patent introduces Li2SiO3 (lithium silicate) as an intermediary substance that mediates between the electrolyte and electrode materials. This intermediary forms a stable protective layer on the electrode surface, preventing direct contact and harmful reactions between the conventional electrolyte and high-voltage cathode materials, thereby extending cycle life while maintaining electrolyte stability
Solution Approach 2:
The patent modifies the electrolyte composition by adding Li2SiO3 to change the chemical parameters of the electrolyte system. This parameter change enables the electrolyte to form stable surface films and resist decomposition at high voltages above 4.2V and elevated temperatures, directly addressing the stability issue
2Use of energy by moving object
If the operating voltage is increased above 4.2V to achieve higher energy density, then the battery capacity increases, but the electrolyte decomposes and generates gas and acidic products that damage the battery
Solution Approach 1:
The patent converts the potentially harmful decomposition reactions into beneficial effects by using Li2SiO3 to catalyze the formation of stable protective films on electrode surfaces. The same high-voltage conditions that would normally cause electrolyte decomposition now promote the formation of stable surface layers that prevent further decomposition and eliminate gas and acidic product generation
Solution Approach 2:
Li2SiO3 acts as a mediator that enables high-voltage operation by forming a protective interface layer. This intermediary layer prevents the electrolyte from coming into direct contact with the cathode material at high voltages, thereby preventing the generation of harmful gases and acidic products while allowing energy density to increase
3Reliability
If LiPF6 is used as the lithium salt to achieve high specific conductivity, then the electrolyte can passivate aluminum current collector, but LiPF6 undergoes thermal decomposition at elevated temperatures to generate strong Lewis acids that trigger undesirable chemical reactions
Solution Approach 1:
Li2SiO3 serves as a thermal stability intermediary that protects LiPF6 from decomposition at elevated temperatures. It forms a thermally stable protective layer that prevents LiPF6 from undergoing thermal decomposition, thereby eliminating the generation of strong Lewis acids while maintaining the electrolyte's ability to passivate aluminum current collector
Solution Approach 2:
The patent changes the thermal parameters of the electrolyte system by incorporating Li2SiO3, which raises the thermal decomposition temperature of the electrolyte components. This parameter change allows the electrolyte to maintain its conductivity and aluminum passivation capabilities at elevated temperatures without generating harmful Lewis acids
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 functionalized matrix additives enhance the cycle life and energy density of lithium-ion batteries by stabilizing the electrolyte, reducing parasitic reactions, and maintaining initial capacity and coulombic efficiency even at elevated temperatures and high voltages.
Implementation Method 1
Solvents, salts, or additives have been incorporated into the electrolyte to decompose on the electrode to form a protective film called a solid electrolyte interphase (SEI)
Implementation Method 2
A liquid electrolyte serves to transport ions between electrodes in a battery
Implementation Method 3
At high voltages, conventional electrolytes can decompose, for example, by catalytic oxidation in the presence of cathode materials, to produce undesirable products that affect both the performance and safety of a battery
Implementation Method 4
Conventional electrolytes may also be degraded by reduction by the electrodes when the cells are charged
Data Source
AI summary
A battery including an anode, a cathode, a separator, and a liquid electrolyte including a lithium salt, a non-aqueous solvent, and an additive compound including a functionalized matrix having a polymer or copolymer or silica. The cathode material can be an NMC or LCO material. The electrode formed from the cathode or anode material can include a matrix additive. The matrix additive can be adhered to the separator or other inert component of the battery.