Molten Lithium Salt Interfacial Layer for Silicon Electrode Resistance

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Solution Overview

Problem

Current energy storage devices face challenges in integrating active and inactive components effectively, leading to high interfacial resistance and impedance, which hampers ion and electron transfer across interfaces, particularly in silicon-based electrodes and solid polymer electrolytes.

Innovation Solution

The introduction of an interfacial additive layer composed of molten lithium-containing salts, such as lithium bis(trifluoromethanesulfonyl)imide, between the silicon-based electrode and the solid polymer electrolyte layer, significantly reducing interfacial resistance and enhancing ion and electron mobility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a silicon based electrode is directly interfaced with a solid polymer electrolyte layer, then the device structure is simple, but the interfacial resistance is high which hampers ion and electron transfer

Engineering Contradiction:

Improveion and electron transfer efficiencyVSAvoidinterface structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A molten lithium-containing salt layer is introduced as an intermediary between the silicon-based electrode and the solid polymer electrolyte layer. This intermediate layer facilitates ion and electron transfer across the interface, reducing interfacial resistance and improving charge transfer efficiency without requiring complex structural modifications to the overall device architecture.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical state parameter of the lithium-containing salt from solid to molten state at the interface. This parameter change enables the salt to better match the mobility characteristics of both the silicon electrode and solid polymer electrolyte, thereby optimizing charge transfer properties at the interface while maintaining structural simplicity.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If component layers are integrated without independent treatment, then the manufacturing process is simple, but the interfacial bonding and charge-conductive properties are suboptimal

Engineering Contradiction:

Improveinterfacial bonding and charge-conductive propertiesVSAvoidcomponent integration process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The molten lithium-containing salt layer is applied to the silicon-based electrode surface before integrating the solid polymer electrolyte layer. This preliminary action prepares the interface with optimal charge-conductive properties beforehand, ensuring strong interfacial bonding and efficient charge transfer while maintaining a straightforward manufacturing process.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the interfacial additive layer is composed of molten lithium-containing salt, then the ion and electron mobility is enhanced, but the device requires temperature control to maintain the molten state

Engineering Contradiction:

Improveion and electron mobilityVSAvoidtemperature control system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes the phase transition property of lithium-containing salts, maintaining them in a molten state through controlled temperature parameters. This parameter control enables the salt to exhibit optimal ionic and electronic conductivity at the interface, enhancing charge mobility while allowing for relatively simple thermal management compared to alternative approaches.

Inventive Principle:

Principle #35Parameter changes

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

This configuration results in a substantial decrease in interfacial impedance, improving the overall performance of energy storage devices by facilitating efficient charge transfer and mass transport, thereby enhancing the device's energy storage capabilities.

Implementation Method 1

The presence of such an interfacial additive layer increases the ion and electron mobile dependent performances at the silicon based electrode interface due to significant decrease in the resistance/impedance that is observed at the respective interface

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

The presence of such an interfacial additive layer increases the ion and electron mobile dependent performances at the silicon based electrode interface

Methodology Applied

Scientific EffectElectron conduction: Conduction (electrical)

Data Source

PatentUS11309585B2Molten ion conductive salt/silicon interface for decreased interfacial resistance

Publication Date: 2022.04.19 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

An interfacial additive layer for decreasing the interfacial resistance/impedance of a silicon based electrode-containing device such as, for example, an energy storage device or a micro-resistor, is disclosed. The interfacial additive layer, which is composed of a molten lithium containing salt, is formed between a silicon based electrode and a solid polymer electrolyte layer of the device. The presence of such an interfacial additive layer increases the ion and electron mobile dependent performances at the silicon based electrode interface due to significant decrease in the resistance/impedance that is observed at the respective interface as well as the impedance observed in the bulk of the device.