Solid Lithium Battery Cathode Interface for Lower Contact Resistance
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Solution Overview
Problem
Solid lithium batteries face challenges with large interface contact resistance at the solid-solid interface between the electrode and the solid electrolyte, which affects electrochemical stability and electrical performance.
Innovation Solution
The design of the solid lithium battery includes a positive electrode layer with a second solid electrolyte, such as oxygen-doped sulfide or lithium indium chloride, and a conductive additive like graphene, which reduces reactivity and enhances electrochemical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a solid-solid interface is used between the electrode and the solid electrolyte, then the battery structure is simplified and energy density is improved, but the interface contact resistance increases and electrochemical stability deteriorates
Solution Approach 1:
The patent introduces a buffer layer comprising oxygen-doped sulfide or lithium indium chloride positioned between the positive electrode and the solid electrolyte. This intermediary layer mediates the interface between the two solid components, reducing contact resistance and preventing direct harmful interactions while maintaining the solid-state structure's energy density advantages.
Solution Approach 2:
The patent employs composite material design by combining oxygen-doped sulfide or lithium indium chloride with the solid electrolyte and electrode materials. This composite approach creates a multi-functional interface layer that simultaneously provides electrical conductivity, chemical stability, and mechanical contact, resolving the contradiction between simplified structure and electrochemical performance.
2Power
If conventional conductive additives are used in the positive electrode layer, then electrical conductivity is improved, but reactivity increases and electrochemical stability worsens
Solution Approach 1:
The patent changes the chemical composition parameters of the conductive additive by using oxygen-doped sulfide or lithium indium chloride instead of conventional carbon-based additives. This parameter change reduces the reactivity of the conductive additive with the solid electrolyte while maintaining adequate electrical conductivity, thus improving electrochemical stability.
Solution Approach 2:
The patent applies local quality by positioning the buffer layer with specific chemical composition (oxygen-doped sulfide or lithium indium chloride) at the critical electrode-electrolyte interface region. This localized material selection addresses the reactivity issue specifically at the interface where side reactions occur, without affecting the overall electrode structure.
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 design improves electrochemical stability while maintaining electrical performance, achieving high energy density and cycle stability, and reducing the risk of corrosion and solid interface accumulation.
Implementation Method 1
a second solid electrolyte, such as oxygen-doped sulfide or lithium indium chloride, which reduces reactivity and enhances electrochemical stability
Implementation Method 2
a conductive additive like graphene, which reduces reactivity and enhances electrochemical stability
Implementation Method 3
during the charging and discharging process, they can reduce the probability of lithium dendrites penetrating the electrolyte and bringing the positive and negative electrodes into contact
Data Source
AI summary
A solid lithium battery includes a negative electrode layer, a solid electrolyte layer, and a positive electrode layer. The solid electrolyte layer includes a first solid electrolyte. The positive electrode layer includes an active material, a second solid electrolyte, a conductive additive, and an adhesive. A material of the second solid electrolyte includes oxygen-doped sulfide or lithium indium chloride and/or a material of the conductive additive includes graphene.