Partial Reduction Surface Treatment for Lithium Battery Electrodes

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Solution Overview

Problem

Transition metal compounds used in lithium batteries, such as LiNiO2 and LiMn2O4, suffer from poor rate capability due to low conductivity, limiting their capacity and performance in high-demand applications.

Innovation Solution

A process involving heating an electroactive material and exposing it to a reducing gas to form a surface-treatment layer, which increases electronic conductivity by partial reduction, enhancing the material's performance in lithium batteries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If transition metal compounds like LiNiO2 and LiMn2O4 are used in lithium batteries, then high capacity is achieved, but poor rate capability occurs due to low conductivity

Engineering Contradiction:

ImprovecapacityVSAvoidrate capability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by creating a surface treatment layer with different chemical composition and properties than the bulk material. The surface layer is partially reduced to have higher electronic conductivity, while the interior bulk material maintains its high capacity characteristics. This resolves the contradiction by making the surface properties different from the bulk properties.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent creates a composite structure consisting of the original transition metal compound bulk material combined with a surface treatment layer. The composite has two distinct regions: the interior providing high capacity and the surface providing high conductivity, thus resolving the contradiction between capacity and rate capability.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the electroactive material is heated to high temperature, then the surface treatment process is effective, but energy consumption increases

Engineering Contradiction:

Improvesurface treatment effectivenessVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent uses parameter changes by varying temperature, reducing gas composition, and exposure time to optimize the surface treatment process. By carefully controlling these parameters, the patent achieves effective surface reduction at moderate temperatures rather than requiring extreme heating, thus balancing treatment effectiveness with energy consumption.

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

The surface-treated electroactive materials exhibit improved electronic conductivity, leading to increased cycle life and power capabilities, with enhanced discharge and charge capacities, particularly in rechargeable lithium batteries.

Implementation Method 1

exposing the electroactive material to a reducing gas to form a surface-treatment layer on the electroactive material... the surface-treatment layer is a layer of the electroactive material which has been partially reduced

Methodology Applied

Scientific EffectPartial reduction: Reduction

Data Source

PatentUS9559354B2Electrode materials

Publication Date: 2017.01.31 UCHICAGO ARGONNE LLC

AI summary

A process for forming a surface-treatment layer on an electroactive material includes heating the electroactive material and exposing the electroactive material to a reducing gas to form a surface-treatment layer on the electroactive material, where the surface-treatment layer is a layer of partial reduction of the electroactive material.