Nitrogen-Doped Carbon Coating for Lithium Ion Battery Electrodes

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Solution Overview

Problem

Phosphate-based electrode materials for lithium ion batteries have insufficient electron conductivity, leading to impaired lithium ion diffusion and reduced battery performance, particularly in high-temperature conditions, where traditional carbon coating methods risk sintering and decreased electrode density.

Innovation Solution

A carbonaceous electron-conductive substance with nitrogen atoms is formed as a thin layer on the surface of electrode active materials, allowing both improved electron conductivity and lithium ion diffusivity without impairing lithium ion diffusion, achieved by mixing an electrode active material, a carbon source, a nitrogen source, and a catalyst, and thermally treating the mixture in a non-oxidizing atmosphere.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high temperature thermal treatment is applied to carbonize organic substance, then electron conductivity of coating is improved, but sintering occurs and electrode density decreases

Engineering Contradiction:
Improveelectron conductivity of coatingVSAvoidelectrode density
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent changes the chemical composition of the coating material by incorporating nitrogen atoms, which allows effective carbonization and conductivity improvement at lower temperatures. This parameter change prevents sintering and maintains electrode density while achieving the desired electron conductivity

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 approach enhances the load characteristics, cycle characteristics, and energy density of lithium ion batteries by maintaining lithium ion diffusion while improving electron conductivity, resulting in a more reliable and durable battery performance.

Implementation Method 1

thermally treating the mixture in a non-oxidizing atmosphere

Methodology Applied
Scientific EffectThermal treatment: Heat Treatment

Implementation Method 2

the carbonaceous electron-conductive substance contains nitrogen atoms

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

improving electron conductivity and lithium ion diffusivity without impairing lithium ion diffusion

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentUS9923207B2Electrode material, electrode and lithium ion battery
Publication Date: 2018.03.20 SUMITOMO METAL MINING CO LTD

AI summary

An electrode material which can improve the mobility of electrons and the mobility of ions at the same time, and, furthermore, does not have a problem of the impairment of the diffusion of lithium ions in a thin layer containing a carbonaceous electron-conductive substance so as to be excellent in terms of load characteristics and energy density, and an electrode and a lithium ion battery are provided. The electrode material of the invention is produced by forming a thin layer made of a carbonaceous electron-conductive substance on surfaces of primary particles made of an electrode active material, in which the carbonaceous electron-conductive substance contains nitrogen atoms.