Silicon-Based Battery Electrolyte Additives for Stable Interphase Layers
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Solution Overview
Problem
Conventional lithium-ion battery electrolytes are costly, inefficient, and limit battery lifetime due to issues with silicon-based anodes and high-voltage cathodes, such as unstable solid electrolyte interphase layers, oxidative instability, and poor cycle life, which hinder the development of high-energy density and safe lithium-ion batteries.
Innovation Solution
The development of new electrolyte additives, including functional compounds like carbonates, oxalates, and peroxides, that form stable, electronically insulating but ionically conducting solid electrolyte interphase (SEI) layers on silicon anodes and cathode electrolyte interphase (CEI) layers, enhancing electrochemical stability, thermal stability, and safety by reducing flammability and oxidative reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium-ion battery electrolytes are used with silicon-based anodes, then the battery can operate, but the solid electrolyte interphase layer becomes unstable and battery lifetime is limited
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by introducing specific additive compounds (carbamates, ureas, thiocyanates, isothiocyanates, cyanates, or isocyanates) at controlled concentrations (0.1-5 wt%). This parameter change transforms the unstable solid electrolyte interphase into a stable protective layer, resolving the contradiction between initial operation and long-term stability.
Solution Approach 2:
The electrolyte additive compounds act as intermediaries that mediate between the silicon-based anode and the conventional electrolyte. These additives form intermediate protective layers (SEI and CEI) that prevent direct harmful interactions, stabilizing the interface and extending battery lifetime while maintaining operational functionality.
2Use of energy by moving object
If high-voltage cathodes are used to increase energy density, then the battery capacity increases, but oxidative instability occurs reducing battery lifetime
Solution Approach 1:
The electrolyte additives serve as protective intermediaries between the high-voltage cathode and the electrolyte solvent. They form a stable cathode electrolyte interphase (CEI) layer that mediates the interface, preventing oxidative reactions while allowing ionic transport, thus enabling high energy density operation with improved reliability.
Solution Approach 2:
The additives perform preliminary protective action by forming stable interphase layers before oxidative degradation can occur. This preemptive formation of protective barriers prevents oxidative instability from developing, allowing the battery to safely operate at high voltages for extended periods.
3Use of energy by moving object
If silicon particles are increased in the anode to improve capacity, then the energy density increases, but the composite material structure becomes complex requiring carbon phases to hold it together
Solution Approach 1:
The patent employs composite material structures combining silicon particles (0-90 wt%) with carbon phases (10-100 wt%). The carbon matrix provides structural integrity and electrical conductivity while accommodating silicon's volumetric expansion. This composite approach enables high silicon content for improved energy density while managing the structural complexity through the reinforcing carbon network.
Solution Approach 2:
The carbon phases are strategically distributed throughout the silicon composite to provide local structural support where needed. The continuous carbon matrix locally reinforces the structure at silicon particle interfaces and boundaries, enabling the system to handle high silicon content without requiring uniform complexity throughout the entire material structure.
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
These additives improve the cycle life, energy density, and safety of silicon anode-based lithium-ion batteries by stabilizing the solid-electrolyte interface, reducing capacity fade, and enhancing thermal stability, while minimizing transition metal ion dissolution and surface resistance.
Implementation Method 1
form stable, electronically insulating but ionically conducting solid electrolyte interphase (SEI) layers on silicon anodes
Implementation Method 2
form stable, electronically insulating but ionically conducting solid electrolyte interphase (SEI) layers on silicon anodes and cathode electrolyte interphase (CEI) layers
Implementation Method 3
enhancing electrochemical stability, thermal stability, and safety by reducing flammability and oxidative reactions
Data Source
AI summary
Electrolytes and electrolyte additives for energy storage devices are disclosed. The energy storage device comprises a first electrode and a second electrode, where one or both of the first electrode and the second electrode is a Si-based electrode, a separator between the first electrode and the second electrode, an electrolyte, and at least one electrolyte additive compound selected from a carbonate, oxalate, trioxidane, peroxide, peroxoate, dioxetanone, oxepane dione, oxetane dione, anhydride, oxalate or 1,4-dioxane-2,3-dione; each of which may be optionally substituted.