Lithium Battery Electrode Active Material with Metal Borate Coating
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Solution Overview
Problem
Lithium composite metal oxides with high nickel content are structurally unstable, leading to reduced lifetime characteristics of lithium secondary batteries due to damage in the fine lattice structure, necessitating the development of a positive active material that improves lifetime while maintaining high capacity.
Innovation Solution
An electrode active material is developed with a core active material having a layered structure, doped with boron and a metal element, and coated with a metal borate compound containing the same metal element, which increases the interlayer distance and stabilizes the lattice, enhancing lithium ion charging and discharging stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high nickel content is increased in lithium composite metal oxide to achieve high capacity, then battery capacity is improved, but structural stability deteriorates leading to lattice damage and reduced lifetime
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core contains high nickel content for high capacity while the shell contains protective elements (aluminum, magnesium, zinc, or calcium) to maintain structural stability. This allows different regions of the material to have different compositions optimized for their specific functions: the nickel-rich core provides capacity while the stable shell prevents lattice degradation.
Solution Approach 2:
The patent uses composite materials by combining nickel-based lithium composite metal oxide with protective metal elements (aluminum, magnesium, zinc, or calcium) in a core-shell configuration. This composite structure integrates the high capacity advantage of nickel-rich materials with the structural stability of protective elements, resolving the contradiction between capacity and stability.
2Quantity of substance
If high nickel content is increased in lithium composite metal oxide to achieve high capacity, then battery capacity is improved, but lifetime characteristics deteriorate due to lattice structure damage
Solution Approach 1:
The core-shell structure with protective elements in the shell prevents lattice structure damage during charge-discharge cycles, thereby extending the lifetime of the battery while maintaining the high capacity provided by the nickel-rich core. The protective shell acts as a barrier that prevents structural degradation over time.
Solution Approach 2:
The protective shell is formed beforehand to cushion and prevent lattice structure damage that would otherwise occur during battery operation. This preemptive protective layer prevents the degradation mechanisms that would reduce lifetime, allowing the high nickel content core to maintain its capacity over extended periods.
3Duration of action of moving object
If dopant amount is increased to improve lifetime characteristics, then structural stability is improved, but capacity may be reduced due to excessive doping
Solution Approach 1:
The patent optimizes the dopant concentration within specific ranges (aluminum: 0.01-0.10 mol%, magnesium: 0.01-0.05 mol%, zinc: 0.01-0.05 mol%, calcium: 0.01-0.05 mol%) to achieve the right balance between structural stability and capacity. These controlled parameter changes ensure sufficient protection without excessive doping that would reduce capacity.
Solution Approach 2:
The dopants are concentrated in the shell region rather than uniformly distributed throughout the entire material. This localized doping provides structural stability where needed at the interfaces and surfaces, while the nickel-rich core maintains its high capacity characteristics.
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 proposed electrode active material improves the lifespan and capacity retention of lithium secondary batteries by stabilizing the lattice structure and facilitating stable lithium ion movement, while also reducing side reactions and improving bonding strength with the current collector.
Implementation Method 1
the first metal element may be configured to contract or expand the layered structure of the core active material
Implementation Method 2
enhancing lithium ion charging and discharging stability
Data Source
AI summary
An electrode active material includes: a core active material having a layered structure and capable of reversibly incorporating and deincorporating lithium; a dopant including boron and a first metal element, wherein the dopant is in the core active material; and a nanostructure disposed on a surface of the core active material and including a metal borate compound including a second metal element, wherein the second metal element is the same as the first metal element.