Sulfurized PAN Positive Electrode Balancing Sulfur Loading and Kinetics

Solution Overview

Problem

Conventional lithium-sulfur batteries with sulfurized polyacrylonitrile positive electrodes have low energy density due to low sulfur percentage, and increasing sulfur percentage compromises kinetic performance and capacity utilization.

Innovation Solution

A positive electrode combining sulfurized polyacrylonitrile with high sulfur percentage (45 wt % to 60 wt %) and low sulfur percentage (30 wt % to 40 wt %) active materials, along with a phosphoric ester additive in the electrolyte, to enhance energy density and retention rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the sulfur percentage in sulfurized polyacrylonitrile is increased to improve energy density, then the energy density increases, but the kinetic performance and capacity utilization deteriorate

Engineering Contradiction:

Improvesulfur percentageVSAvoidkinetic performance

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The positive electrode active material is segmented into two distinct components: first sulfurized polyacrylonitrile with high sulfur percentage (45-60 wt%) for energy density, and second sulfurized polyacrylonitrile with low sulfur percentage (30-40 wt%) for kinetic performance. This segmentation allows each component to fulfill its specific function without compromise

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the positive electrode are assigned different sulfur percentages based on local functional requirements. The high sulfur percentage material (first active material) provides energy density in regions where capacity is prioritized, while the low sulfur percentage material (second active material) maintains kinetic performance in regions requiring fast reaction rates

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If the sulfur percentage in sulfurized polyacrylonitrile is increased to improve energy density, then the energy density increases, but the capacity utilization deteriorates

Engineering Contradiction:

Improvesulfur percentageVSAvoidcapacity utilization

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The positive electrode active material is segmented into two distinct components: first sulfurized polyacrylonitrile with high sulfur percentage (45-60 wt%) for energy density, and second sulfurized polyacrylonitrile with low sulfur percentage (30-40 wt%) for kinetic performance. This segmentation allows each component to fulfill its specific function without compromise

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the positive electrode are assigned different sulfur percentages based on local functional requirements. The high sulfur percentage material (first active material) provides energy density in regions where capacity is prioritized, while the low sulfur percentage material (second active material) maintains kinetic performance in regions requiring fast reaction rates

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20240290977A1Positive electrode and electrochemical apparatus and electronic apparatus using same

Publication Date: 2024.08.29 NINGDE AMPEREX TECHNOLOGY LTD

AI summary

A positive electrode including a first positive electrode active material and a second positive electrode active material, where the first positive electrode active material is sulfurized polyacrylonitrile with a sulfur percentage of 45 wt % to 60 wt %, and the second positive electrode active material is sulfurized polyacrylonitrile with a sulfur percentage of 30 wt % to 40 wt %. The positive electrode increases energy density and energy density retention rate of the electrochemical apparatus.