Polymeric Additive Electrolyte for High-Voltage Cathode Stability
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Solution Overview
Problem
Conventional electrolytes in lithium-ion batteries are unstable at high voltages, leading to decomposition and deterioration of battery performance and safety, limiting the use of high energy cathode materials like LiCoO2 and LiNi0.33Mn0.33CO0.33O2 to only about 50% of their theoretical capacity.
Innovation Solution
A battery design incorporating a lithium salt, non-aqueous solvent, and polymeric additive compound electrolyte that forms a protective solid electrolyte interphase (SEI) on the cathode, preventing oxidative decomposition and enhancing stability for operation at voltages above 4.3V, while maintaining anode stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional electrolytes are used in lithium-ion batteries, then the batteries can operate at standard voltages, but the electrolytes decompose at high voltages above 4.3V, leading to deterioration of performance and safety
Solution Approach 1:
The patent introduces a protective film (SEI - solid electrolyte interphase) as an intermediary layer between the electrolyte and the cathode material. This film acts as a mediator that prevents direct contact and harmful oxidation reactions between the conventional electrolyte and the high-voltage cathode, enabling stable operation at voltages above 4.3V without compromising electrolyte stability
Solution Approach 2:
The protective film is formed preliminarily on the cathode surface before the battery undergoes normal operation at high voltages. This pre-formed barrier prevents the electrolyte decomposition that would otherwise occur during high-voltage charging, allowing the battery to safely utilize high-energy cathode materials like LiCoO2 and LiNi0.33Mn0.33Co0.33O2
2Quantity of substance
If high energy cathode materials like LiCoO2 and LiNi0.33Mn0.33CO0.33O2 are used to increase capacity, then the theoretical capacity increases, but only about 50% can be utilized due to electrolyte degradation at the required high voltages
Solution Approach 1:
The protective SEI film serves as an intermediary barrier that enables the full utilization of high-energy cathode materials. By preventing electrolyte oxidation at the cathode surface, it allows the battery to operate at the high voltages (above 4.3V) required to access the full theoretical capacity of materials like LiCoO2 and LiNi0.33Mn0.33Co0.33O2, thereby achieving both high capacity and long cycle life
Solution Approach 2:
The invention changes the electrochemical parameters at the cathode interface by introducing the protective film, which alters the local environment to prevent electrolyte decomposition. This parameter change enables stable operation at higher voltages, allowing the battery to achieve greater than 50% capacity utilization of high-energy cathode materials
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 significantly improves cycle life and coulombic efficiency, allowing for higher capacity utilization of high energy cathode materials by preventing electrolyte degradation and maintaining performance characteristics.
Implementation Method 1
solvents, salts, or additives have been incorporated into the electrolyte to decompose to form a protective film called a solid electrolyte interphase (SEI)
Implementation Method 2
An electrolyte serves to transport ions and prevent electrical contact between electrodes in a battery
Implementation Method 3
electrochemical cells
Data Source
AI summary
Described herein are materials for use in electrolytes that provide a number of desirable characteristics when implemented within batteries, such as high stability during battery cycling up to high temperatures, high voltages, high discharge capacity, high coulombic efficiency, and excellent retention of discharge capacity and coulombic efficiency over several cycles of charging and discharging. In some embodiments, a high voltage electrolyte includes a base electrolyte and a set of additive compounds, which impart these desirable performance characteristics.