Sulfur Positive Electrode Mix with Li-S-Br-P Solid Electrolyte
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Solution Overview
Problem
Conventional lithium-ion batteries with sulfur-based solid electrolytes face limitations in achieving high capacity and discharge voltage due to high internal resistance and low discharge voltage, as well as high production costs associated with materials like Ge.
Innovation Solution
A positive electrode mix comprising a sulfur-based active material with a solid electrolyte containing Li, S, Br, and P, with specific composition and structural characteristics, including a crystalline component and a conductive material with fine pores, to enhance ion conductivity and discharge voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a sulfur-based active material is used to increase capacity, then the theoretical capacity increases, but the internal resistance increases and discharge voltage decreases
Solution Approach 1:
A solid electrolyte containing Li, S, Br, and P elements is introduced as an intermediary substance between the sulfur-based active material and the electrode structure. This solid electrolyte mediates ion transport while maintaining structural stability, thereby reducing internal resistance and improving discharge voltage without sacrificing the high capacity benefits of sulfur-based materials.
Solution Approach 2:
The invention employs a composite structure combining sulfur-based active material with a specially formulated solid electrolyte containing multiple elements (Li, S, Br, P). This composite material approach allows the system to simultaneously achieve high capacity from sulfur while benefiting from the improved ion conductivity and structural stability provided by the multi-element solid electrolyte matrix.
2Reliability
If Ge-based materials are used to improve solid electrolyte performance, then ion conductivity increases, but production cost increases significantly
Solution Approach 1:
The invention replaces expensive Ge-based solid electrolytes with a cost-effective solid electrolyte formulation using abundant elements (Li, S, Br, P). This substitution maintains adequate ion conductivity performance while dramatically reducing material costs, making the technology economically viable for commercial applications.
Solution Approach 2:
The invention changes the compositional parameters of the solid electrolyte by selecting alternative elements (Li, S, Br, P) instead of Ge, while optimizing their ratios to achieve the desired ion conductivity. This parameter optimization allows cost-effective materials to perform at levels previously only achievable with expensive Ge-based compounds.
3Power
If oxide-based positive electrode active material is used, then output power increases, but capacity is limited
Solution Approach 1:
The invention merges the advantages of oxide-based materials (high output power) with sulfur-based materials (high capacity) by using the multi-element solid electrolyte as a bridging medium. This combination allows the electrode system to simultaneously achieve high power output and high capacity utilization, overcoming the limitations of using either material type alone.
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 positive electrode mix enables a lithium-ion battery with higher discharge voltage and improved safety, while reducing internal resistance and production costs.
Implementation Method 1
This solid electrolyte has a high ion conductivity of 10^-3[S/cm] or more
Data Source
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AI summary
A positive electrode mix including a solid electrolyte and a sulfur-based active material, wherein the solid electrolyte comprises a Li element or a Na element; a S element; and a halogen element selected from the group consisting of I, Br, Cl and F.