Metal Amide Electrolyte Additives for Stable Si Anode Interfaces

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Solution Overview

Problem

Conventional lithium-ion battery electrolytes are costly, cumbersome, and inefficient, limiting battery lifetime due to instability with silicon-based anodes and high-voltage cathodes, leading to issues like irreversible capacity loss and poor cycling stability.

Innovation Solution

The use of metal amide bases as electrolyte additives forms a stable solid electrolyte interphase (SEI) layer on silicon anodes and a cathode electrolyte interphase (CEI) layer, enhancing electrochemical stability, thermal stability, and reducing electrolyte consumption, while also improving energy density and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrolytes are used with silicon-based anodes, then battery capacity can be achieved, but battery lifetime is limited due to instability and irreversible capacity loss

Engineering Contradiction:

Improvebattery lifetimeVSAvoidelectrolyte stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces metal amide bases as intermediary substances that mediate between the silicon-based anode and the conventional electrolyte. These additives form stable interphase layers (SEI and CEI) that act as protective intermediaries, preventing direct harmful interactions between the unstable silicon anode/conventional electrolyte combination, thereby extending battery lifetime while maintaining electrolyte stability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical composition parameters of the electrolyte by incorporating metal amide bases (such as LiHMDS, NaHMDS, KHMDS) at specific concentrations (0.1-10 wt%). This parameter change transforms the electrolyte's interfacial properties, enabling it to form stable protective layers on silicon anodes and high-voltage cathodes, thus improving both battery lifetime and electrolyte stability

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If silicon-based anodes are used to increase energy density, then capacity is improved, but cycling stability deteriorates due to poor interface stability

Engineering Contradiction:

Improvebattery capacityVSAvoidcycling stability

Core Design Contradiction:

Quantity of substanceVSDuration of action of stationary object

Solution Approach 1:

The metal amide bases perform preliminary action by pre-forming stable solid electrolyte interphase (SEI) layers on the silicon anode surface before the battery enters normal cycling operation. This preliminary protective layer formation prevents subsequent degradation during cycling, allowing the battery to maintain high capacity from silicon-based anodes while achieving improved cycling stability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent creates a composite interfacial structure consisting of the silicon-based anode, the metal amide base-derived protective layer, and the conventional electrolyte. This composite material approach at the interface enables the system to simultaneously achieve high capacity (from silicon) and good cycling stability (from the stable composite interface)

Inventive Principle:

Principle #40Composite materials

3Use of energy by moving object

If conventional electrolytes are used with high-voltage cathodes, then energy density is improved, but thermal stability deteriorates leading to safety issues

Engineering Contradiction:

Improveenergy densityVSAvoidthermal stability

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The metal amide bases act as intermediary protective agents between the high-voltage cathode and the conventional electrolyte. They form cathode electrolyte interphase (CEI) layers that mediate the interaction, preventing direct thermal degradation reactions while allowing the battery to operate at high voltages for improved energy density without compromising thermal stability

Inventive Principle:

Principle #24Intermediary (Mediator)

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 metal amide-based additives improve the cycle life and safety of lithium-ion batteries by stabilizing the electrode interfaces, reducing capacity fade, and increasing thermal stability, thus addressing the limitations of conventional electrolytes with silicon-based anodes and high-voltage cathodes.

Implementation Method 1

The use of metal amide bases as electrolyte additives forms a stable solid electrolyte interphase (SEI) layer on silicon anodes

Methodology Applied

Scientific EffectSolid electrolyte interphase formation:

Implementation Method 2

forms a stable solid electrolyte interphase (SEI) layer on silicon anodes and a cathode electrolyte interphase (CEI) layer

Methodology Applied

Scientific EffectCathode electrolyte interphase formation:

Implementation Method 3

enhancing electrochemical stability, thermal stability, and reducing electrolyte consumption

Methodology Applied

Scientific EffectInterface stabilization:

Data Source

PatentUS11848419B2Metal amide bases as electrolyte additives for Si anode-based Li-ion batteries

Publication Date: 2023.12.19 ENEVATE CORP

AI summary

Electrolytes and electrolyte additives for energy storage devices comprising metal amide bases are disclosed. The energy storage device comprises a first electrode and a second electrode, wherein at least one of the first electrode and the second electrode is a Si-based electrode, a separator between the first electrode and the second electrode and an electrolyte composition comprising at least one electrolyte additive comprising a metal amide base compound.