Low-Carbon Lithium Transition Metal Phosphate Composite

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Solution Overview

Problem

Current materials for lithium-ion battery electrodes do not achieve the required electrode density, leading to insufficient battery capacity, particularly in applications like automotive use, due to insufficient powder compaction density.

Innovation Solution

A composite material comprising lithium transition metal phosphate particles (such as Fe, Co, Mn, or Ni) with a carbon content of 0.5 to 1.3% by weight, a BET surface area ≤ 12.5 m²/g, a shaking weight > 600 g/l, and a powder resistance < 70 Ω cm, which increases pressing density and thus battery capacity by approximately 5% or more.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrode materials with higher carbon content are used, then electrical conductivity is improved, but electrode density and battery capacity decrease

Engineering Contradiction:
Improveelectrical conductivityVSAvoidelectrode density
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the carbon content parameter to a specific range (0.5-1.3 wt%) and controls particle size parameters to achieve optimal balance between conductivity and density. By precisely controlling these parameters, the invention resolves the contradiction between needing sufficient carbon for conductivity and minimizing carbon to maximize density.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system consisting of lithium transition metal phosphate particles combined with carbon in optimized proportions. This composite structure allows the material to simultaneously achieve good electrical conductivity through carbon networks while maintaining high electrode density through optimized particle packing and minimal carbon content.

Inventive Principle:
Principle #40Composite materials

2Reliability

If more carbon is added to the composite material, then electrical conductivity increases, but pressing density decreases

Engineering Contradiction:
Improveelectrical conductivityVSAvoidpressing density
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent identifies and controls critical parameters including carbon content (0.5-1.3 wt%), particle size distribution, and surface area to achieve optimal pressing density. By adjusting these parameters within specific ranges, the invention maximizes carbon efficiency to maintain conductivity while minimizing volume occupied by carbon to achieve high pressing density.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If conventional materials are used, then ease of manufacture is maintained, but battery capacity is insufficient for automotive applications

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidbattery capacity
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent modifies key material parameters (carbon content to 0.5-1.3 wt%, particle size, surface area) to achieve higher battery capacity while maintaining compatibility with existing manufacturing processes. The invention uses conventional synthesis methods but optimizes the resulting material parameters to deliver superior capacity for automotive applications.

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 composite material enhances electrode density and battery capacity by increasing pressing density, allowing for higher volumetric energy density and improved cycle stability, while using significantly less carbon than previously thought necessary, making it suitable for industrial use.

Implementation Method 1

The pressed density of the material can be roughly correlated with the electrode density or the density of the so-called active material and also the battery capacity. The higher the pressing density, the higher the capacity of the battery.

Methodology Applied
Scientific EffectParticle packing:

Data Source

PatentEP2576439B1Carbon-lithium transition metal phosphate composite material having a low carbon content
Publication Date: 2016.08.24 JOHNSON MATTHEY PLC
  • EP2576439B1 patent drawingFigure 1
  • EP2576439B1 patent drawingFigure 2
  • EP2576439B1 patent drawing

AI summary

The invention relates to a composite material containing particles of a lithium transition metal phosphate and carbon having a carbon content of = 1.4 wt %. The invention further relates to an electrode containing the composite material, and to a secondary lithium-ion battery containing an electrode that comprises the composite material.