Lithium-Ion Battery Electrolyte for Silicon Anode Cycle Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries with silicon-based negative electrodes face challenges due to volume expansion during lithiation and delithiation, leading to particle pulverization, loss of electrical contact, and unstable solid-electrolyte interface formation, resulting in capacity fading.
Innovation Solution
Incorporating a nickel-rich positive electroactive material with a silicon-based negative electroactive material and an electrolyte containing succinic anhydride as an additive, which helps in forming a stable cathode electrolyte interphase, reducing side reactions and improving cycling stability and discharge rate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based negative electrode materials are used to achieve high specific capacity, then the theoretical capacity increases significantly, but volume expansion during lithiation and delithiation causes particle pulverization and unstable solid-electrolyte interface formation
Solution Approach 1:
The patent introduces an electrolyte additive (cyclic sulfate ester) as an intermediary substance that mediates between the silicon-based electrode and the electrolyte. This additive forms a stable interfacial layer that acts as a protective barrier, preventing direct harmful interactions while allowing lithium ion transport, thus resolving the contradiction between high capacity and cycling stability
Solution Approach 2:
The patent changes the chemical composition parameter of the electrolyte by adding cyclic sulfate ester (1,3-propanesultone or 1,4-butanesultone) at specific concentrations (0.1-5 wt%). This parameter change leads to the formation of a stable solid-electrolyte interface with different protective properties, enabling silicon to maintain both high capacity and cycling stability
2Quantity of substance
If silicon-based negative electrode materials are used to achieve high specific capacity, then the theoretical capacity increases significantly, but volume expansion leads to loss of electrical contact
Solution Approach 1:
The patent effectively creates a flexible protective thin film interface through the electrolyte additive. This interfacial layer accommodates the volume expansion of silicon during lithiation while maintaining continuous electrical contact and preventing particle pulverization, thus resolving the contradiction between high capacity and contact stability
3Quantity of substance
If nickel-rich positive electroactive materials are used to improve capacity capability, then the capacity increases, but structural stability may be compromised
Solution Approach 1:
The electrolyte additive acts as an intermediary that forms protective interfacial layers on both electrodes, including the nickel-rich positive electrode. This stabilizes the interface and prevents structural degradation, allowing the system to maintain both high capacity from nickel-rich materials and structural stability
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 enhances the cycling stability and discharge rate performance of lithium-ion batteries by mitigating volume expansion issues in silicon-based electrodes, leading to improved capacity retention and reduced impedance.
Implementation Method 1
The electrolyte may include greater than or equal to about 1 wt. % to less than or equal to about 3 wt. % of an electrolyte additive. The electrolyte additive may be selected from the group consisting of: succinic anhydride (SA), maleic anhydride, N-carboxyanhydride, glutaric anhydride, isatin anhydride, citraconic anhydride, and combinations thereof.
Data Source
AI summary
An electrochemical cell that cycles lithium ions is provided. The electrochemical cell may include a first porous electrode, a second porous electrode, and a separating layer disposed between the first electrode and the second electrode. The first porous electrode includes an electrolyte intermingled with a nickel-rich positive electroactive material. The second porous electrode includes the electrolyte intermingled a silicon-based negative electroactive material. The electrolyte includes greater than or equal to about 1 wt. % to less than or equal to about 3 wt. % of an electrolyte additive and a solvent mixture. The electrolyte additive may be selected from the group consisting of: succinic anhydride (SA), maleic anhydride, N-carboxyanhydride, glutaric anhydride, isatin anhydride, citraconic anhydride, and combinations thereof. The solvent mixture may include ethylene carbonate (EC) and dimethyl carbonate (DMC) in mass ratio of about 3:7.