Lithium Molybdate Core-Shell Material for Battery Capacity

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Solution Overview

Problem

Current lithium secondary batteries face challenges with high manufacturing costs and unstable supply of traditional positive active materials like LiCoO2, and existing Ni-based oxide composites struggle to balance packing density, thermal stability, and capacity.

Innovation Solution

A lithium molybdate composite with a core-shell structure is developed, where the core has specific XRD peaks and an amorphous Li-M-O—C shell, enhancing electrochemical properties and capacity, and is manufactured through heat treatment processes involving lithium molybdenum oxide and transition metal sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If LiCoO2 is used as positive active material, then high discharge voltage and high energy density are achieved, but manufacturing cost is expensive and stable supply is not guaranteed

Engineering Contradiction:

Improvedischarge voltageVSAvoidmanufacturing cost

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent replaces expensive LiCoO2 with cheaper LiMnO3 as the positive active material. LiMnO3 is abundant, low-cost, and provides comparable electrochemical performance, effectively substituting the expensive material with a more economical alternative while maintaining high discharge voltage and energy density

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a composite structure by coating LiMnO3 particles with a protective layer containing Li2SiO3 and carbon. This composite approach enhances the thermal stability and electrochemical performance of LiMnO3, making it a viable replacement for LiCoO2 while maintaining cost advantages

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If Ni-based oxide composite is used to increase capacity per unit volume, then capacity is improved, but thermal stability and capacity properties cannot be satisfied simultaneously

Engineering Contradiction:

Improvecapacity per unit volumeVSAvoidthermal stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality modification by coating the LiMnO3 particles with a specific protective layer containing Li2SiO3 and carbon. This localized coating enhances thermal stability at the particle surface while maintaining the high capacity properties of the bulk LiMnO3 material, resolving the contradiction between capacity and thermal stability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent creates a composite material system where LiMnO3 is combined with Li2SiO3 and carbon coating. This composite structure provides both high capacity (from LiMnO3) and enhanced thermal stability (from Li2SiO3 and carbon layer), simultaneously satisfying both requirements that cannot be achieved with pure Ni-based oxides

Inventive Principle:

Principle #40Composite materials

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 lithium molybdate composite achieves improved capacity and lifetime properties for lithium batteries, outperforming existing materials like LiCoO2, LiMnO, NCM, and LiFePO4, while offering thermal stability and increased charge retention.

Implementation Method 1

performing a first heat treatment to the lithium molybdenum oxide at a temperature from about 500° C. to about 1,100° C. in a reducing atmosphere

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 2

performing a first heat treatment to the lithium molybdenum oxide at a temperature from about 500° C. to about 1,100° C. in a reducing atmosphere

Methodology Applied

Scientific EffectReduction: Reduction

Implementation Method 3

the shell includes an amorphous coating layer containing Li-M-O—C(wherein M is at least one metal selected from sodium (Na), potassium (K), cesium (Cs), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), yttrium (Y), lanthanum (La), titanium (Ti), zirconium (Zr), vanadium (V), manganese (Mn), iron (Fe), copper (Co), nickel (Ni), silver (Ag), gold (Au), zinc (Zn), and aluminum (Al))

Methodology Applied

Scientific EffectAmorphous coating formation: Deposition (physical)

Implementation Method 4

having a first peak at a diffraction angle (2θ) of 20.65±0.1° and a second peak at a diffraction angle (2θ) of 30.50±0.1°, in an X-ray diffraction (XRD) measurement using a CuKα ray

Methodology Applied

Scientific EffectX-ray diffraction: X-Ray

Data Source

PatentUS10535869B2Positive active material, lithium battery including the same, and method of manufacturing the positive active material

Publication Date: 2020.01.14 SAMSUNG SDI CO LTD

AI summary

Provided are a positive active material, a lithium battery including the positive active material, and a method of manufacturing the positive active material. The positive active material includes a lithium molybdate composite having a core-shell structure. The lithium molybdate composite acts as a sacrificial positive electrode in a positive electrode of a battery. The positive active material is able to increase charge capacity of a lithium battery, and accordingly is able to improve lifetime properties of a lithium battery.