Sulfur Conversion Cathode with Composite Electrolyte for Low Impedance
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Solution Overview
Problem
Existing lithium-ion batteries face challenges in achieving lower cell impedance, increased active material utilization, and enhanced cathode ion transport and kinetics, which are crucial for improving energy storage efficiency and performance.
Innovation Solution
The development of an electrochemical cell with a sulfuric conversion electroactive material and a solid state electrolyte, specifically designed to include oxysulfides or sulfides, along with a limited solvating liquid electrolyte and a porous polymer separator, to optimize cathode performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liquid electrolytes are used in lithium-ion batteries, then the battery can operate with standard electrolyte conductivity, but the cell impedance remains high and active material utilization is limited
Solution Approach 1:
The patent employs a composite electrolyte system combining solid state electrolyte (oxysulfide or sulfide) with limited solvating liquid electrolyte. This composite approach allows the solid state electrolyte to provide stable ion conduction pathways while the liquid electrolyte fills pores and provides additional ionic conductivity, achieving both low impedance and high active material utilization without sacrificing either parameter
Solution Approach 2:
The cathode structure utilizes porous polymer separators and porous electrode architectures that allow the limited solvating liquid electrolyte to penetrate and wet the active material particles effectively. The porous structure increases surface area for electrochemical reactions while the solid state electrolyte maintains structural integrity, enabling high active material utilization with reduced impedance
2Ease of manufacture
If traditional cathode structures are used, then manufacturing processes remain simple, but ion transport and kinetics in the cathode are insufficient
Solution Approach 1:
The solid state electrolyte acts as an intermediary between the liquid electrolyte and the active material particles. It provides a stable interface that enhances ion transport kinetics while maintaining compatibility with conventional cathode manufacturing processes. The solid state electrolyte particles are mixed with the active material and binder in a slurry that can be applied using standard coating techniques
Solution Approach 2:
The patent changes the physical and chemical parameters of the electrolyte system by introducing solid state oxysulfide or sulfide electrolytes with specific ionic conductivity characteristics. This parameter change enhances cathode ion transport and kinetics while the slurry preparation and coating processes remain consistent with conventional manufacturing methods
3Quantity of substance
If sulfur-based electroactive materials are used to increase capacity, then energy density improves, but cell impedance increases and cycle stability decreases
Solution Approach 1:
The solid state electrolyte (oxysulfide or sulfide) forms a composite structure with sulfur-based electroactive materials that stabilizes the interface during charge-discharge cycles. This composite approach prevents sulfur dissolution and maintains low impedance over extended cycling, achieving both high capacity and excellent cycle stability
Solution Approach 2:
The limited solvating liquid electrolyte is used in controlled amounts to provide initial wetting and ionic conductivity during early cycles, after which the solid state electrolyte takes over as the primary ion conduction medium. This approach allows the liquid electrolyte to perform its useful function temporarily and then be effectively replaced by the more stable solid state electrolyte system
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
This configuration results in lower cell impedance, increased active material utilization, and improved cathode ion transport and kinetics, leading to enhanced specific capacity and cycle stability of the lithium-ion battery.
Implementation Method 1
a solid state electrolyte including an oxysulfide or a sulfide
Implementation Method 2
a liquid electrolyte including a limited solvating liquid electrolyte
Implementation Method 3
a separator including a porous polymer separator
Implementation Method 4
an electrode including a sulfuric conversion electroactive material
Data Source
AI summary
An electrochemical cell including an electrode including a sulfuric conversion electroactive material, and a solid state electrolyte comprising an oxysulfide; a liquid electrolyte; a separator; and a negative electrode.