Conductive Material Coating for High-Voltage Battery Capacity Retention
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries face low capacity retention rates due to electrolyte decomposition on conductive materials at high voltages, leading to metal elution from positive electrode active materials.
Innovation Solution
A non-aqueous electrolyte secondary battery design where the surface of the conductive material is coated with a layer primarily composed of P, O, C, and H, reducing electrolyte decomposition and enhancing capacity retention rates by maintaining an upper limit voltage of 4.5 V or more with respect to lithium's oxidation-reduction potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the upper limit voltage is increased to 4.5 V or more to increase energy density, then the energy density is improved, but the electrolyte decomposes on the conductive material surface leading to low capacity retention rate
Solution Approach 1:
A coating layer comprising phosphorus, oxygen, carbon, and hydrogen is introduced as an intermediary between the conductive material and the electrolyte. This coating layer prevents direct contact and chemical reaction between the electrolyte and conductive material, thereby preventing electrolyte decomposition and metal elution while allowing efficient lithium ion transport, thus resolving the contradiction between high voltage operation and capacity retention
Solution Approach 2:
The surface of the conductive material is selectively modified by forming a coating layer with specific compositional characteristics (phosphorus, oxygen, carbon, and hydrogen). This local modification protects only the critical conductive material surface from electrolyte decomposition while maintaining the overall battery structure and function, enabling high voltage operation with improved capacity retention
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 coating layer effectively reduces electrolyte decomposition, thereby increasing the capacity retention rate of the battery while allowing for efficient lithium ion movement, even at high voltages.
Implementation Method 1
the surface of the conductive material is coated with a coating layer mainly formed of P, O, C and H
Implementation Method 2
efficient lithium ion movement, even at high voltages
Data Source
AI summary
A non-aqueous electrolyte secondary battery in which it is possible to increase a capacity retention rate is provided.A non-aqueous electrolyte secondary battery is provided which includes: a positive electrode layer that includes a positive electrode active material and a conductive material; a negative electrode layer; and a non-aqueous electrolytic solution that is arranged between the positive electrode layer and the negative electrode layer, where an upper limit voltage is equal to or more than 4.5 V with respect to the oxidation-reduction potential of lithium, and the surface of the conductive material is coated with a coating layer mainly formed of P, O, C and H.