Porous Sulfur Composite Powder for High-Rate Alkali Metal-Ion Cathodes
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Solution Overview
Problem
Alkali metal-ion batteries, particularly those using sulfur as the positive electrode, face challenges with low electron conductivity and slow diffusion of alkali metal-ions, leading to insufficient discharge capacity at high current densities.
Innovation Solution
A composite powder comprising a carbon material with pores, impregnated with a first heat-impregnating material containing alkali metal ion-conductive elements like lithium, boron, oxygen, phosphorus, halogen, or antimony, and a second heat-impregnating material of elemental sulfur, which are melted and filled into the pores to enhance conductivity and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If sulfur is used as the positive electrode to achieve large theoretical capacity, then battery capacity is improved, but electron conductivity is insufficient
Solution Approach 1:
The patent uses a composite structure combining sulfur with conductive materials (carbon materials, metal compounds, or conductive polymers) to simultaneously achieve high capacity and good conductivity. The conductive material forms a network that facilitates electron transport while sulfur provides the active material for high capacity.
Solution Approach 2:
The patent employs porous conductive materials as the matrix to hold sulfur particles. The porous structure provides large surface area for sulfur deposition, maintains good electron conductivity through the conductive matrix, and allows efficient ion diffusion pathways.
2Reliability
If sulfur-carbon composite is used to improve electron conductivity, then conductivity is improved, but discharge capacity at high current density is insufficient due to slow alkali metal-ion diffusion
Solution Approach 1:
The patent creates local conductivity enhancement by incorporating conductive materials specifically at the sulfur particle surfaces and within the porous matrix. This localized conductive network ensures efficient electron transport at the reaction sites while maintaining fast ion diffusion pathways in the porous structure.
Solution Approach 2:
The patent introduces conductive polymers or metal compounds that form three-dimensional conductive networks within the porous structure. This multi-dimensional conductive pathway system enhances electron transport in multiple directions while preserving the porous architecture for fast ion diffusion.
3Reliability
If solid electrolyte is mechanically mixed with sulfur-carbon composite to improve lithium ionic conductivity, then ionic conductivity is improved, but discharge capacity at high current density remains insufficient
Solution Approach 1:
The patent combines multiple functional materials (sulfur, conductive materials, and solid electrolyte components) into a single integrated porous composite structure. This merging creates synergistic effects where the conductive matrix and solid electrolyte components work together to simultaneously enhance both electron conductivity and ion transport, achieving high discharge capacity at high current densities.
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 composite powder significantly improves discharge capacity and rate properties at high current densities, enabling better performance in alkali metal-ion batteries.
Implementation Method 1
the first heat-impregnating material and the second heat-impregnating material are impregnated into the pores by melting
Implementation Method 2
heating a carbon material having pores, and an alkali metal ion-conductive material or a precursor thereof comprising one or more elements selected from lithium, boron, oxygen, phosphorus, halogen and antimony at a temperature equal to or higher than the melting point
Data Source
AI summary
The present disclosure provides a composite powder including a carbon material having pores, a first heat-impregnating material and a second heat-impregnating material.