Lithium Battery Anode Carbon Composition for High-Rate Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Rechargeable lithium batteries face challenges in achieving high-rate charge and discharge characteristics and electrical conductivity due to limitations in the design and composition of their negative active materials, particularly in preventing volume expansion and maintaining optimal resistance levels.

Innovation Solution

A negative active material composition for lithium batteries is developed, incorporating 8-50 wt% of rod-shaped crystalline carbon with a maximum length of 75 μm to 160 μm and an aspect ratio of 4 to 30, combined with 50-92 wt% of particle-shaped or shorter rod-shaped crystalline carbon, applied in a specific distribution on a current collector to enhance conductivity and reduce resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If rod-shaped crystalline carbon with large aspect ratio is used to improve electrical conductivity and high-rate charge-discharge characteristics, then power performance is improved, but volume expansion occurs during lithium ion intercalation and deintercalation

Engineering Contradiction:

Improvehigh-rate charge and discharge characteristicsVSAvoidvolume expansion of negative active material

Core Design Contradiction:

PowerVSVolume of moving object

Solution Approach 1:

The patent applies nesting by filling the internal voids and interstitial spaces of the rod-shaped crystalline carbon (first active material) with particle-shaped crystalline carbon (second active material). This nested structure allows the particle-shaped carbon to occupy the empty spaces within the rod-shaped carbon framework, preventing volume expansion during lithium ion intercalation while maintaining the high-rate charge-discharge characteristics provided by the rod-shaped carbon's aspect ratio.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Power

If conventional negative active materials are used, then manufacturing is simple, but resistance is high and power performance is limited

Engineering Contradiction:

Improveelectrical conductivityVSAvoidcomplexity of negative active material composition

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

The patent applies composite materials by combining two distinct types of crystalline carbon with different morphologies: rod-shaped crystalline carbon (first active material) with high aspect ratio for electrical conductivity and power performance, and particle-shaped crystalline carbon (second active material) for filling voids and preventing volume expansion. This composite structure achieves superior electrical conductivity and power performance while managing the complexity through a defined weight ratio range (30:70 to 70:30).

Inventive Principle:

Principle #40Composite materials

3Volume of moving object

If only particle-shaped crystalline carbon is used, then volume expansion is minimized, but high-rate charge and discharge characteristics are insufficient

Engineering Contradiction:

Improvevolume stability of negative active materialVSAvoidhigh-rate charge and discharge characteristics

Core Design Contradiction:

Volume of moving objectVSPower

Solution Approach 1:

The patent applies segmentation by dividing the negative active material into two functional components with distinct roles: rod-shaped crystalline carbon (first active material) that provides high-rate charge-discharge characteristics through its high aspect ratio and electrical conductivity, and particle-shaped crystalline carbon (second active material) that minimizes volume expansion by filling voids. This segmentation of functions allows each component to optimize its specific role while working together in a composite structure.

Inventive Principle:

Principle #1Segmentation

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 proposed composition improves high-rate charge and discharge characteristics, reduces resistance, and prevents volume expansion, leading to enhanced power performance and capacity retention in lithium batteries.

Implementation Method 1

an active material capable of intercalating and deintercalating lithium ions

Methodology Applied

Scientific EffectIntercalation:

Implementation Method 2

generates electrical energy due to the oxidation and reduction reaction when lithium ions are intercalated and deintercalated

Methodology Applied

Scientific EffectOxidation and reduction reaction: Redox Reactions

Data Source

PatentUS20230268484A1Negative active material for rechargeable lithium battery, negative electrode including same, and rechargeable lithium battery including same

Publication Date: 2023.08.24 SAMSUNG SDI CO LTD

AI summary

A negative active material for a rechargeable lithium battery, a negative electrode including the same, and a rechargeable lithium battery including the same, the negative active material including about 8 wt % to about 50 wt % of a first active material; and about 50 wt % to about 92 wt % of a second active material, all wt % being based on a total weight of the negative active material, wherein the first active material includes a rod-shaped crystalline carbon having a maximum length of about 75 μm to about 160 μm.