Si-C Composite Anode Electrolyte for High-Density Cycle-Stable Batteries
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in maintaining high energy density while preventing increased resistance at room and high temperatures, and ensuring cycle-life characteristics as the content of Si-based active materials in the negative electrode active material increases, leading to rapid electrolyte loss and decreased cycle life.
Innovation Solution
A rechargeable lithium battery design incorporating a negative electrode with a Si—C composite mixed with a separate carbon-based compound, paired with an electrolyte containing two specific additives that stabilize lithium salts and absorb on the positive electrode surface, reducing side reactions and improving high-temperature characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the content of Si-based active material in the negative electrode active material is increased, then energy density is improved, but resistance increases at room temperature and high temperature
Solution Approach 1:
The patent introduces a mediator substance (graphene or carbon nanotubes) between the Si-based active material and the electrolyte. This intermediary layer prevents direct harmful interactions while allowing beneficial electrochemical reactions, thereby reducing resistance increase at room and high temperatures while maintaining high energy density from the Si-based material.
Solution Approach 2:
The patent creates a composite negative electrode active material by combining Si-based active material with conductive carbon materials (graphene or carbon nanotubes). This composite structure leverages the high capacity of Si-based materials while the conductive carbon network provides stable electron transport pathways, preventing resistance increase and maintaining reliability at various temperatures.
2Use of energy by moving object
If the content of Si-based active material in the negative electrode active material is increased, then energy density is improved, but cycle-life decreases
Solution Approach 1:
The conductive carbon material acts as a mediator that maintains structural integrity during charge-discharge cycles. It provides a stable framework that accommodates the expansion and contraction of Si-based active material, preventing particle degradation and maintaining long-term cycle-life while preserving high energy density.
Solution Approach 2:
The composite structure of Si-based active material combined with conductive carbon materials creates a robust electrode architecture. The carbon component provides mechanical strength and electrical conductivity that persists over many cycles, while the Si-based material delivers high capacity, achieving both improved energy density and extended cycle-life.
3Use of energy by moving object
If the content of Si-based active material in the negative electrode active material is increased, then energy density is improved, but electrolyte loss increases rapidly
Solution Approach 1:
The conductive carbon material serves as a protective intermediary layer between the Si-based active material and the electrolyte. This barrier reduces direct contact and harmful side reactions between the electrolyte and Si-based material, thereby minimizing electrolyte decomposition and loss while maintaining the high energy density benefits of the Si-based active material.
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 battery achieves high energy density while suppressing resistance increases at room and high temperatures, securing improved cycle-life characteristics through the synergistic effect of the additives and Si—C composite, enhancing overall battery performance.
Implementation Method 1
the first additive stabilizing the lithium salt
Implementation Method 2
the second additive absorbing on the positive electrode surface
Implementation Method 3
a negative electrode including a negative electrode active material including a Si—C composite
Data Source
AI summary
A rechargeable lithium battery including a positive electrode, a negative electrode, and an electrolyte is provided. The electrolyte includes a non-aqueous organic solvent, a lithium salt, a first additive, and a second additive. The negative electrode includes a negative electrode active material including a Si—C composite mixed with a separate carbon-based compound.