Multilayered Lithium Battery Electrodes for Output and Capacity
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Solution Overview
Problem
Lithium secondary batteries face challenges in simultaneously achieving high output and energy characteristics due to limitations in cathode and anode active materials, such as low stability, resource constraints, and poor cycle characteristics.
Innovation Solution
A lithium secondary battery design featuring a cathode with a spinel-structured lithium manganese oxide active material layer and a layer-structured lithium composite oxide active material layer, combined with an anode having an amorphous carbon-based active material layer and a crystalline carbon-based, silicon, or tin-based material layer, to enhance both output and capacity characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiCoO2 is used as cathode active material, then cycle characteristics are improved, but cost increases and resource availability decreases
Solution Approach 1:
The cathode active material is divided into two separate layers: a spinel-structured lithium manganese oxide layer (first layer) and a layer-structured lithium composite oxide layer (second layer). This segmentation allows each layer to contribute different properties - the spinel layer provides structural stability and the layer-structured layer provides high capacity, thereby improving cycle characteristics without relying solely on expensive LiCoO2
Solution Approach 2:
The invention uses composite oxide materials - specifically a spinel-structured lithium manganese oxide combined with a layer-structured lithium composite oxide containing nickel, cobalt, and manganese. This composite approach combines the advantages of different material structures to achieve both stability and high performance while reducing dependence on scarce cobalt resources
2Ease of manufacture
If lithium manganese oxide is used as cathode active material, then cost and environmental friendliness are improved, but capacity and cycle characteristics deteriorate
Solution Approach 1:
The cathode is segmented into two functional layers: the spinel lithium manganese oxide layer provides structural stability and the layer-structured lithium composite oxide layer (containing Ni, Co, Mn) provides high capacity. This segmentation allows lithium manganese oxide to contribute its cost and environmental advantages while the composite oxide layer compensates for the capacity limitation
Solution Approach 2:
The invention creates a composite cathode structure combining spinel lithium manganese oxide with layer-structured lithium composite oxide. The layer-structured component contains nickel and cobalt in controlled amounts to enhance capacity while the spinel component maintains structural integrity, achieving a balance between cost, environmentality, and performance
3Productivity
If amorphous carbon-based active material is used for anode, then discharge capacity and rate characteristics are improved, but energy density and reversibility deteriorate
Solution Approach 1:
The anode is divided into two layers: a first anode active material layer containing amorphous carbon-based material (providing high discharge capacity and rate characteristics) and a second anode active material layer containing crystalline carbon-based material (providing high energy density and good reversibility). This segmentation allows each layer to optimize for its specific function
Solution Approach 2:
The anode uses a composite structure combining amorphous carbon and crystalline carbon materials. The amorphous carbon provides high surface area and fast reaction kinetics for excellent rate characteristics, while the crystalline carbon provides stable intercalation sites for high reversibility and energy density, achieving synergistic effects
4Power
If charge balance between cathode and anode is not maintained, then output characteristics of one electrode are improved, but battery life characteristics deteriorate
Solution Approach 1:
Both cathode and anode are segmented into two layers each, allowing independent optimization of charge balance. The cathode has spinel and layer-structured layers while the anode has amorphous and crystalline carbon layers. This segmentation enables tuning of lithium insertion/extraction capacity on both electrodes to achieve charge balance
Solution Approach 2:
The invention adjusts the thickness ratios and material compositions of the four active material layers to control the charge balance. By changing parameters such as the ratio of spinel to layer-structured cathode material and amorphous to crystalline anode material, the lithium capacity is balanced between electrodes, preventing side reactions and improving battery life
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 multi-layered approach improves the battery's output and capacity characteristics, leading to increased energy density and reduced degradation, while maintaining excellent rate characteristics and impregnating properties with the electrolyte solution.
Implementation Method 1
a cathode in which a cathode collector; a first cathode active material layer including a spinel-structured lithium manganese oxide active material on at least one surface of the cathode collector; and a second cathode active material layer including a layer-structured lithium composite oxide active material on the first cathode active material layer are sequentially formed
Implementation Method 2
an anode in which an anode collector; a first anode active material layer including an amorphous carbon-based active material on at least one surface of the anode collector; and a second anode active material layer including any one selected from the group consisting of a crystalline carbon-based material, transition metal oxide, a silicon (Si)-based material, and a tin (Sn)-based material
Data Source
Figure 1
AI summary
A lithium secondary battery of the present invention may simultaneously improve high output and high capacity characteristics by including a first active material layer having high output characteristics and a second active material layer having high capacity characteristics respectively on a cathode collector and an anode collector.