Solid-State Cell Interlayer Structure for Low-Pressure Lithium Plating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional solid-state electrochemical cells with thin lithium metal anodes suffer from high pressure requirements and short cycle life due to lithium dendrite formation, which increases electronic resistance and reduces battery life.
Innovation Solution
An interlayer comprising a mixture of carbon materials and metal, such as silicon, is positioned between the current collector and separator layers, allowing lithium metal to accumulate internally and maintain robust interfaces, reducing the need for high pressure applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium ions fully diffuse through the interlayer and collect as lithium metal at the interface, then energy density increases, but a gap forms between the current collector and interlayer during discharge, increasing electronic resistance and decreasing battery life
Solution Approach 1:
The interlayer is pre-designed with a porous structure and specific material composition (carbon materials, metal particles, binder) that anticipates the lithium accumulation process. This preliminary structural design ensures that when lithium ions diffuse and accumulate as lithium metal, the interlayer maintains robust physical contact with the current collector, preventing gap formation and maintaining low electronic resistance throughout cycling
Solution Approach 2:
The interlayer employs a composite material system consisting of carbon materials (for conductivity), metal particles (for lithium accumulation and structural stability), and binder (for cohesion). This composite structure enables the interlayer to simultaneously achieve high energy density through lithium metal formation while maintaining reliable electrical contact and extending battery cycle life
2Reliability
If high pressure is applied to form the layers back together during discharge, then contact between current collector and interlayer is restored, but the complexity and cost of pressure supply equipment increases, negating energy density benefits
Solution Approach 1:
The interlayer's porous structure and material composition enable it to self-maintain robust physical contact with the current collector throughout the charge-discharge cycles. The structural design allows the interlayer to accommodate lithium accumulation and release while inherently maintaining contact, eliminating the need for external pressure supply equipment and preserving the energy density advantages of the thin-anode design
3Volume of moving object
If a thin layer of lithium wetting material is used to replace thick carbon anode, then volume and weight are reduced, but the battery requires high pressure maintenance and has short cycle life
Solution Approach 1:
The interlayer acts as an intermediary between the thin lithium wetting material anode and the separator/cathode. This intermediate layer with its porous structure and composite materials enables the thin anode design to achieve both high energy density and long cycle life by facilitating robust interfaces and enabling lithium accumulation without the need for high pressure maintenance
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 interlayer design enhances energy density while enabling low-pressure operation, improving cycle life and maintaining contact between layers, thus extending battery life.
Implementation Method 1
The current interlayer design allows for lithium ions to fully diffuse though the interlayer where the lithium collects as lithium metal at the interface between the interlayer and the current collector
Implementation Method 2
An interlayer comprising a mixture of carbon materials and metal, such as silicon, is positioned between the current collector and separator layers, allowing lithium metal to accumulate internally and maintain robust interfaces
Data Source
AI summary
Solid-state electrochemical cells include a first current collector, an interlayer, a separator layer, a cathode layer, and a second current collector. The interlayer includes a metal and a mix of carbon materials. When the electrochemical cell is charged, the interlayer splits into a top layer and a bottom layer and a layer of lithium metal forms between the top layer and the bottom layer.