Cerium-Silicon Cage Anode Material for Stable Li-Ion Capacity

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Solution Overview

Problem

Existing negative electrode active materials for secondary batteries, particularly those containing tin, face challenges such as high weight, high cost, and volume changes during charge and discharge, which are unsuitable for mobile applications like electric cars.

Innovation Solution

A lightweight and cost-effective intermetallic compound with a cage structure is used as the negative electrode active material, composed of cerium and silicon atoms, which allows stable lithium ion insertion and desorption, enhancing capacity density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an intermetallic compound containing Sn as a major component is used as a negative electrode active material, then the battery achieves stable lithium ion insertion and desorption, but the battery weight increases and manufacturing cost rises

Engineering Contradiction:

Improvestability of lithium ion insertion and desorptionVSAvoidbattery weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The invention changes the compositional parameters by replacing Sn with an equal molar amount of Al, transforming the intermetallic compound from Sn-containing (e.g., La3Ni2Sn7) to Al-containing (e.g., La3Ni2Al7). This parameter substitution maintains the cage structure and electrochemical stability while significantly reducing weight and cost, as Al is both lighter and more abundant than Sn.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention substitutes expensive Sn with inexpensive Al, using a cheaper material to achieve the same functional purpose. Al is abundant, low-cost, and when used in the specific intermetallic compound structure, provides equivalent stability for lithium ion insertion and desorption without the weight penalty of Sn.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Quantity of substance

If an alloy-type material containing Si is used as a negative electrode active material to achieve high theoretical capacity density, then the battery energy density increases, but the material undergoes great volume changes during charge and discharge

Engineering Contradiction:

Improvetheoretical capacity densityVSAvoidvolume stability during charge and discharge

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The invention creates a composite intermetallic compound structure combining rare earth elements (La, Ce), transition metals (Ni, Co, Mn, Fe), and Al/Si. This composite structure integrates the high capacity potential of Si-containing materials with the volume stability of the intermetallic cage structure, where the framework atoms (including Al or Si) form a stable lattice that accommodates lithium ion insertion and desorption with minimal volume change.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention assigns different functional roles to different parts of the material structure. The cage framework atoms (including Al or Si) provide structural stability and volume resistance during charge-discharge cycles, while the rare earth and transition metal atoms contribute to high theoretical capacity density. This local functional differentiation allows the material to simultaneously achieve high capacity and volume stability.

Inventive Principle:

Principle #3Local quality

3Quantity of substance

If an intermetallic compound with cage structure containing 8-16 second atoms is used as negative electrode active material, then the capacity density increases to 100 mAh/g or more, but the structural complexity increases

Engineering Contradiction:

Improvecapacity densityVSAvoidstructural complexity of cage configuration

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The invention optimizes the numerical parameter of cage atoms to fall within the specific range of 8-16 atoms. This parameter optimization achieves the breakthrough of 100 mAh/g or more capacity density while maintaining manageable structural complexity. The cage structure with this specific atom count provides sufficient capacity through multiple lithium ion insertion sites while remaining synthetically accessible and structurally characterizable.

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 intermetallic compound achieves a high capacity density of 100 mAh/g or more, improving the performance of secondary batteries for mobile applications by reducing weight and cost while maintaining structural stability.

Implementation Method 1

the intermetallic compound having a cage structure is capable of insertion and desorption of lithium ions

Methodology Applied

Scientific EffectLithium ion insertion and desorption: Absorption (physical)

Data Source

PatentUS12614721B2Negative-electrode active material for secondary batteries, and secondary battery

Publication Date: 2026.04.28 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A negative electrode active material for a secondary battery includes an intermetallic compound having a cage structure. The cage structure is constituted of at least one first atom located within a cage, and a plurality of second atoms arranged in a cage-like form so as to surround the first atom. The first atom is a cerium atom, and the plurality of the second atoms include 8 or more and 17 or less silicon atoms.