Lithium-Ion Cathode Composition for High-Voltage Cycle Stability

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Solution Overview

Problem

Existing lithium-ion secondary batteries face challenges with high energy density, cycle performance, safety, and reliability, particularly at high temperatures and high charge voltages, leading to capacity degradation and instability.

Innovation Solution

A secondary battery design incorporating a positive electrode active material with a layered rock-salt crystal structure containing lithium, cobalt, oxygen, and magnesium, along with an ionic liquid electrolyte, which suppresses crystal structure collapse and enhances stability, allowing for high charge voltages and temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional positive electrode active materials are used to achieve high energy density, then capacity increases, but cycle performance deteriorates and capacity degradation occurs at high temperatures and high charge voltages

Engineering Contradiction:

ImprovecapacityVSAvoidcycle performance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the positive electrode active material by incorporating specific ratios of nickel, cobalt, and manganese elements, along with fluorine substitution, to achieve a balanced material that provides both high capacity and excellent cycle stability at elevated temperatures and voltages

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite positive electrode active material combining multiple metal elements (Ni, Co, Mn) with fluorine substitution, creating a multi-component composite structure that synergistically improves both capacity and cycle performance while maintaining stability under harsh operating conditions

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If high charge voltage is applied to increase energy density, then capacity increases, but crystal structure collapses and reliability decreases

Engineering Contradiction:

Improveenergy densityVSAvoidcrystal structure stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent modifies the crystal structure parameters by introducing fluorine substitution at specific lattice positions and adjusting the metal element ratios, which strengthens the crystal framework and enables it to withstand high charge voltages without collapsing, thereby maintaining both high energy density and structural stability

Inventive Principle:

Principle #35Parameter changes

3Speed

If conventional electrolytes are used to achieve rapid charging, then charging speed increases, but safety deteriorates at high temperatures

Engineering Contradiction:

Improvecharging speedVSAvoidsafety at high temperatures

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical and chemical parameters of the electrolyte by selecting specific carbonate solvents with appropriate boiling points and dielectric constants, and by using lithium salts with high thermal stability, enabling rapid charging while maintaining safety at elevated temperatures through optimized electrolyte composition

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 design achieves a high-capacity, long-life secondary battery that can be rapidly charged and safely operated at high temperatures with improved cycle performance and reduced capacity loss, utilizing a stable ionic liquid electrolyte to prevent structural changes.

Implementation Method 1

an ionic liquid electrolyte, which suppresses crystal structure collapse and enhances stability, allowing for high charge voltages and temperatures

Methodology Applied

Scientific EffectElectrochemical stabilization:

Data Source

PatentUS20250273739A1Secondary battery, electronic device, and vehicle

Publication Date: 2025.08.28 SEMICON ENERGY LAB CO LTD

AI summary

A lithium-ion secondary battery having high capacity and excellent charge and discharge cycle performance is provided. A secondary battery having high capacity is provided. A secondary battery having excellent charge and discharge performance is provided. A secondary battery in which a decrease in capacity is suppressed even at high temperatures is provided. The secondary battery includes a positive electrode, a negative electrode, an electrolyte solution, and an exterior body. The positive electrode includes a positive electrode active material. The positive electrode active material contains lithium, cobalt, oxygen, magnesium, and fluorine. The number of magnesium atoms contained in the positive electrode active material is greater than or equal to 0.001 times and less than or equal to 0.1 times the number of cobalt atoms contained in the positive electrode active material. The positive electrode active material includes a region having a layered rock-salt crystal structure. The electrolyte solution contains an ionic liquid. The exterior body includes a metal layer and a polymer layer stacked over the metal layer. The polymer layer includes a region in contact with the electrolyte solution.