Porous Conductive Cathode for Solid-State Lithium Sulfur Batteries
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Solution Overview
Problem
All-solid state lithium sulfur batteries face challenges with low sulfur availability as a cathode active material, leading to reduced energy density and stability issues due to sulfur loss during reversible oxidation and reduction, which affects discharging capacity and lifespan.
Innovation Solution
A cathode comprising a porous conductive material with sulfur in its backbone, where sulfur is injected into the pores, allowing increased sulfur availability and maintaining structural stability by acting as a foothold for sulfur active material during charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If sulfur is used as a cathode active material in all solid-state lithium sulfur batteries, then energy density is improved, but sulfur availability decreases and structure collapses during reversible oxidation and reduction
Solution Approach 1:
The patent uses porous carbon material as the cathode structure to increase the surface area and porosity, allowing more sulfur to be loaded while maintaining structural integrity during charge-discharge cycles. The porous structure prevents collapse and maintains sulfur availability.
Solution Approach 2:
The patent creates a composite structure where sulfur is combined with conductive carbon material. This composite approach allows sulfur to provide high energy density while the carbon matrix maintains structural stability and sulfur availability during electrochemical reactions.
2Use of energy by moving object
If sulfur is used as a cathode active material, then energy density is improved, but discharging capacity and lifespan decrease due to sulfur loss during reversible oxidation and reduction
Solution Approach 1:
The porous carbon structure provides a stable matrix that retains sulfur during repeated oxidation and reduction cycles, preventing sulfur loss and maintaining discharging capacity over extended battery lifespan.
Solution Approach 2:
The conductive carbon material acts as a sacrificial or stable matrix that can accommodate sulfur's volume changes and prevent its loss, effectively making the carbon structure a durable supporting element that extends battery life.
3Use of energy by moving object
If porous material is used as conductive material to increase sulfur injected amount, then energy density is improved, but sulfur availability remains low
Solution Approach 1:
The patent optimizes the porous structure of the carbon material to provide both high surface area for sulfur loading and adequate pore connectivity for ion transport, ensuring that increased sulfur content does not compromise sulfur availability.
Solution Approach 2:
The patent creates local regions with different properties within the cathode structure, where sulfur is concentrated in accessible pore regions while maintaining conductive pathways, ensuring that the sulfur that is loaded remains electrochemically active and available.
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 enhances discharging capacity and extends the lifespan of the battery by ensuring sulfur participation in oxidation/reduction reactions and maintaining the battery structure, as evidenced by improved capacity retention and reduced capacity reduction rates over multiple cycles.
Implementation Method 1
sulfur participation in oxidation/reduction reactions
Data Source
AI summary
A cathode for an all solid-state lithium sulfur battery includes a porous conductive material, which is manufactured from a precursor containing sulfur, and contains the sulfur in a backbone and a sulfur active material, which is injected into pores of the porous conductive material.