Alkali Source Cathode for Rechargeable Battery Capacity

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Solution Overview

Problem

Current secondary batteries, particularly lithium-ion batteries, face limitations in specific capacity and cycleability, with non-lithiated cathode materials and metallic lithium anodes leading to safety concerns and irreversible capacity losses.

Innovation Solution

The development of an as-prepared cathode for secondary batteries incorporating an alkali source material such as lithia (Li2O) that supplies lithium ions, combined with non-lithiated cathode active materials and a porous carbon catalyst, enhancing specific capacity and cycle stability while avoiding lithium dendrite formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If non-lithiated cathode materials are used, then specific capacity is improved, but cycleability deteriorates due to irreversible capacity losses

Engineering Contradiction:

Improvespecific capacityVSAvoidcycleability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

Lithia (Li2O) is incorporated into the cathode structure in advance before battery operation. During initial charging, the lithia decomposes to release lithium ions that compensate for irreversible losses at the anode, pre-establishing a balanced lithium distribution that maintains cathode efficiency throughout cycling.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the chemical composition parameter of the cathode by incorporating alkali source materials (Li2O, Li2O2, Li2S, LiF, LiCl, Li2Br) in specific quantities (1-40 wt%). This compositional modification enables the cathode to supply additional lithium ions dynamically, maintaining electrochemical balance and improving cycle stability.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If metallic lithium anodes are used, then specific capacity is improved, but safety deteriorates due to lithium dendrite formation

Engineering Contradiction:

Improvespecific capacityVSAvoidlithium dendrite formation

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

Lithia acts as an intermediary lithium source within the cathode structure, releasing lithium ions gradually during charging. This mediates the lithium flux, preventing the rapid lithium deposition that causes dendrite formation on metallic lithium anodes, while still enabling high capacity operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the potential harm of excessive lithium extraction from cathode materials (which causes structural degradation) into a benefit by using lithia as a sacrificial lithium source. The lithia decomposes preferentially to supply lithium, protecting the main cathode material structure while preventing anode dendritization.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If lithiated cathode materials are used, then cycle stability is improved, but specific capacity is limited by irreversible capacity losses

Engineering Contradiction:

Improvecycle stabilityVSAvoidspecific capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The lithia component is designed to be sacrificial - it is discarded (decomposes) during initial charging to release lithium ions that compensate for anode irreversible losses. This discarding action recovers capacity that would otherwise be lost, enabling the use of non-lithiated high-capacity cathode materials.

Inventive Principle:

Principle #34Discarding and recovering

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 high specific capacity and safe operation with improved cycleability, as the alkali source material compensates for anode irreversible capacity losses and maintains cathode efficiency, enabling the use of non-lithiated materials in lithium-ion batteries without generating lithium dendrites.

Implementation Method 1

an as-prepared cathode for secondary batteries incorporating an alkali source material such as lithia (Li2O) that supplies lithium ions

Methodology Applied

Scientific EffectIon supply:

Implementation Method 2

combined with non-lithiated cathode active materials and a porous carbon catalyst

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 3

enabling the use of non-lithiated materials in lithium-ion batteries without generating lithium dendrites

Methodology Applied

Scientific EffectReversible insertion:

Data Source

PatentUS9478794B2Electroactive materials for rechargeable batteries

Publication Date: 2016.10.25 UCHICAGO ARGONNE LLC

AI summary

A secondary battery including a cathode having a primary cathode active material and an alkaline source material selected from the group consisting of Li2O, Li2O2, Li2S, LiF, LiCl, Li2Br, Na2O, Na2O2, Na2S, NaF, NaCl, and a mixture of any two or more thereof; an anode having an anode active material; an electrolyte; and a separator.