Lithium-Rich Composite Current Collector for SEI Lithium Compensation
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Solution Overview
Problem
Conventional positive electrode current collectors in lithium-ion batteries are limited to a single function of carrying the electrode and collecting currents, lacking additional benefits.
Innovation Solution
A lithium-rich composite current collector is developed, comprising a polymer layer with metal and lithium-rich layers, enhancing strength, ductility, and compensating for active lithium consumption during SEI film formation, thereby increasing battery capacity and cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional high-purity aluminum foil is used as the current collector, then the manufacturing process is well-established and the structure is simple, but the current collector can only carry the positive electrode and collect currents without providing additional benefits
Solution Approach 1:
The current collector is designed with multiple functional layers: the aluminum foil layer provides current collection and structural support, while the lithium-rich layer compensates for active lithium consumption and enhances capacity. This multi-functional design allows a single component to perform both current collection and lithium supplementation functions simultaneously.
Solution Approach 2:
The current collector uses a composite structure combining aluminum foil and lithium-rich materials (such as lithium carbonate, lithium hydroxide, or lithium oxide). This composite material approach integrates the electrical conductivity and mechanical strength of aluminum with the lithium-containing properties of the lithium-rich layer, achieving both structural integrity and additional lithium supply functionality.
2Strength
If the current collector is made of single metal material to simplify the structure, then the manufacturing is easier and the structure is simpler, but the strength and ductility are insufficient
Solution Approach 1:
The composite structure combines aluminum foil with lithium-rich materials, where the aluminum provides mechanical strength and ductility, while the lithium-rich layer adds functional properties. This composite approach enhances the overall mechanical properties compared to single-metal alternatives.
Solution Approach 2:
The current collector is divided into distinct layers: the aluminum foil layer provides the mechanical framework with high strength and ductility, while the lithium-rich layer is segmented into fine particles distributed on the aluminum surface. This segmentation allows each layer to optimize its own mechanical properties while working together as a unified structure.
3Reliability
If the lithium-rich layer is added to compensate for active lithium consumption, then the battery capacity and cycle life increase, but the device complexity increases
Solution Approach 1:
The lithium-rich layer is pre-applied to the aluminum foil current collector before battery assembly. This preliminary action ensures that the lithium compensation function is already in place, allowing the lithium-rich layer to immediately compensate for active lithium consumption during SEI film formation and subsequent cycling, thereby extending cycle life from the outset.
Solution Approach 2:
The composite material structure integrates the lithium-rich layer with the aluminum foil, creating a unified current collector that simultaneously provides mechanical support, electrical conductivity, and lithium compensation. This integration reduces the need for separate lithium supplementation mechanisms, managing overall device complexity.
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 composite current collector improves tensile strength and ductility, enhances electron transport capability, and increases active lithium content, resulting in higher capacity and extended cycle life.
Implementation Method 1
evaporating metal to deposit a metal layer on a surface of a polymer layer by using vacuum coating equipment
Implementation Method 2
the lithium metal therein can compensate for the initial consumption of active lithium in the process of forming the solid electrolyte interface (SEI) film
Data Source
AI summary
The present application relates to a lithium-rich composite current collector for use in a positive electrode and a method for preparing the same. The lithium-rich composite current collector includes a polymer layer, two deposited aluminum layers, and two lithium-rich layers, wherein the two deposited aluminum layers are respectively disposed on two opposite surfaces of the polymer layer; and the two lithium-rich layers are respectively disposed on surfaces of the two deposited aluminum layers away from the polymer layer. By disposing the deposited aluminum layers and the lithium-rich layers on the surfaces of the polymer layer, the lithium-rich composite current collector has relatively high strength and ductility. Additionally, due to the presence of the lithium-rich layers, the lithium metal therein can compensate for the initial consumption of active lithium in the process of forming the solid electrolyte interface (SEI) film in the battery, and increase the amount of active lithium in the battery, which can increase the capacity and the cycle life of the battery.