Coated Irreversible Additive for Silicon-Anode Capacity Loss

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Solution Overview

Problem

Lithium secondary batteries using silicon-based negative electrodes face irreversible capacity issues due to electrolyte decomposition, leading to energy density loss, and existing sacrificial positive electrode materials like Li2NiO2 cause structural changes and side reactions, such as impurity and gas generation.

Innovation Solution

An irreversible additive with a trigonal crystal structure and a LISICON-based coating layer is used to stabilize the lithium nickel oxide surface, minimizing structural changes and reducing gas generation during charging and discharging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Li2NiO2 with orthorhombic structure is used as sacrificial positive electrode material, then irreversible capacity is compensated, but structural changes cause impurity generation and gas generation

Engineering Contradiction:

Improveirreversible capacity compensationVSAvoidimpurity generation and gas generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the crystal structure parameter of Li2NiO2 from orthorhombic to trigonal system, and adjusts the voltage range parameter to 3.5-4.25 V, which eliminates structural changes during charging-discharging cycles while maintaining irreversible capacity compensation function

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material by coating Li2NiO2 particles with Li5FeO4, forming a core-shell structure where the Li5FeO4 coating layer prevents direct contact between Li2NiO2 and electrolyte, thereby suppressing side reactions and harmful factor generation

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If silicon-based negative electrode active material is used to increase capacity, then energy density is improved, but electrolyte decomposition forms SEI layer causing irreversible capacity

Engineering Contradiction:

Improvebattery capacityVSAvoidirreversible capacity

Core Design Contradiction:

Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent converts the harmful irreversible capacity loss into a beneficial feature by intentionally using Li2NiO2 as a sacrificial material that provides irreversible capacity to compensate for the SEI layer formation, thereby enabling the silicon-based negative electrode to achieve its full theoretical capacity

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 additive enhances lithium ion mobility, stabilizes the structure, and suppresses side reactions, effectively compensating for irreversible capacity without decreasing energy density.

Implementation Method 1

a coating layer which is positioned on the surface of the lithium nickel oxide and includes a compound

Methodology Applied

Scientific EffectCoating layer stabilization: Coatings

Implementation Method 2

An irreversible additive including lithium nickel oxide having a trigonal crystal structure

Methodology Applied

Scientific EffectIon mobility enhancement: Fast Ion Conductor

Data Source

PatentUS12456724B2Irreversible additive, positive electrode material including irreversible additive, and lithium secondary battery including positive electrode material

Publication Date: 2025.10.28 LG ENERGY SOLUTION LTD

AI summary

An irreversible additive includes an oxide having a trigonal crystal structure and represented by Formula 1, and a coating layer positioned on a surface of the oxide and including a compound represented by Formula 2. A positive electrode material including the irreversible additive and a lithium secondary battery including the positive electrode material including the irreversible additive are also provided.