Silicon Anode Batteries with Supplemental Lithium

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Solution Overview

Problem

Lithium ion batteries for consumer electronics face challenges in achieving high volumetric energy density and long cycle life due to significant irreversible capacity loss and morphological changes in silicon-based anode materials during cycling.

Innovation Solution

Incorporating a silicon-based anode with supplemental lithium and graphitic carbon, along with advanced electrode design and stabilization coatings, to compensate for irreversible capacity loss and stabilize the anode during cycling, while maintaining high energy density and power output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If silicon-based anode material is used to increase capacity, then volumetric energy density is improved, but irreversible capacity loss increases during cycling

Engineering Contradiction:

Improvevolumetric energy densityVSAvoidirreversible capacity loss

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by adding supplemental lithium to the battery before cycling begins. This supplemental lithium is specifically intended to compensate for the irreversible capacity loss that occurs during the first charge cycle of the silicon-based anode, ensuring that the battery maintains its designed capacity from the outset rather than suffering permanent capacity reduction.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs parameter changes by adjusting the amount of supplemental lithium added to the battery. The specification indicates that the supplemental lithium should be present in an amount of at least about 100% to about 170% of the negative electrode first cycle irreversible capacity loss, allowing optimization of the balance between initial capacity and long-term cycling performance.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If silicon-based anode material is used to increase capacity, then volumetric energy density is improved, but cycling stability deteriorates due to morphological changes

Engineering Contradiction:

Improvevolumetric energy densityVSAvoidcycling stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies composite materials by combining silicon-based anode material with graphitic carbon active material. This composite structure leverages the high capacity of silicon while using graphite to provide structural stability and maintain cycling performance. The graphitic carbon acts as a buffer that accommodates the morphological changes of silicon during lithium insertion and extraction cycles.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent uses graphitic carbon as an intermediary material between the silicon-based anode and the electrolyte. This intermediary layer helps to stabilize the anode structure during cycling, reducing the direct impact of morphological changes on overall battery reliability while still allowing lithium ion transport.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If high capacity anode material is used, then energy density is improved, but first cycle irreversible capacity loss increases

Engineering Contradiction:

Improveenergy capacityVSAvoidfirst cycle irreversible capacity loss

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by pre-calculating and adding the appropriate amount of supplemental lithium to compensate for the expected irreversible capacity loss. This allows the battery to start with full designed capacity rather than losing permanent capacity in the first cycle.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs beforehand cushioning by incorporating supplemental lithium as a buffer against irreversible capacity loss. This supplemental lithium acts as a reserve that compensates for the capacity lost during the first cycle, ensuring that the battery maintains its intended energy capacity throughout its cycling life.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 achieves a high volumetric energy density of at least 500 Wh/l and maintains 70% of the 5th cycle discharge capacity at the 150th cycle, with improved cycling stability and reduced energy and power output degradation.

Implementation Method 1

a negative electrode comprising a silicon based active material

Methodology Applied

Scientific EffectAlloying reaction: Chemical Bonding

Implementation Method 2

an electrolyte comprising lithium ions

Methodology Applied

Scientific EffectIon transport: Diffusion

Implementation Method 3

supplemental lithium and an electrolyte comprising lithium ions

Methodology Applied

Scientific EffectElectrochemical reaction: Redox Reactions

Data Source

PatentUS11476494B2Lithium ion batteries with high capacity anode active material and good cycling for consumer electronics

Publication Date: 2022.10.18 IONBLOX INC

AI summary

Battery designs are provided that exhibit commercially suitable cycling properties for consumer electronics with silicon based active materials in the electrodes. The batteries can have stacked or wound electrodes and suitable electrode designs.