Olivine-Spinel Cathode Composition for Low-Temperature Li-Ion Capacity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving high energy density and capacity while maintaining economic viability.
Innovation Solution
A positive electrode active material comprising first particles with an olivine structure, second particles with a spinel structure, and third particles, along with a specific composition and dopants, is used to enhance the performance of rechargeable lithium batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional positive electrode materials are used, then manufacturing cost is reduced, but energy density and capacity are insufficient
Solution Approach 1:
The patent employs a composite positive electrode material consisting of Li-rich layered oxide particles (providing high capacity), coated with a dual-layer structure of lithium nickel manganese oxide spinel (enhancing stability and voltage) and lithium iron phosphate olivine (improving safety and low-temperature performance). This composite structure achieves high energy density while maintaining manufacturing feasibility through established coating processes.
Solution Approach 2:
The patent applies different functional coatings to different aspects of the electrode material: the spinel layer addresses surface stability and voltage characteristics, while the olivine layer targets safety and low-temperature performance. This localized functional differentiation allows each coating to optimize specific properties without compromising overall energy density.
2Quantity of substance
If high-capacity materials are used, then energy density is improved, but charge and discharge efficiency deteriorates
Solution Approach 1:
The spinel and olivine coatings serve as intermediary layers between the Li-rich layered oxide core and the electrolyte. These intermediaries facilitate efficient lithium ion transport while stabilizing the electrode structure, thereby maintaining high charge and discharge efficiency despite the high capacity of the core material.
Solution Approach 2:
The patent utilizes the inherent porous structure of the spinel and olivine coating layers to enable rapid lithium ion diffusion. The porous architecture provides multiple pathways for ion transport, reducing resistance and improving charge-discharge rates while preserving the high capacity of the underlying Li-rich material.
3Quantity of substance
If Li-rich layered oxide is used, then capacity is improved, but structural stability deteriorates
Solution Approach 1:
The patent creates a composite structure where the Li-rich layered oxide core (providing high capacity) is encapsulated by spinel and olivine coatings (providing structural stability). This composite architecture prevents direct exposure of the unstable core to the electrolyte, maintaining structural integrity during cycling.
Solution Approach 2:
The spinel and olivine coatings are applied beforehand to the Li-rich layered oxide particles to provide a protective buffer. This pre-established protective layer prevents structural degradation and phase transitions that would otherwise occur in the high-capacity material during electrochemical cycling.
4Temperature
If conventional materials are used, then manufacturing simplicity is maintained, but low-temperature performance deteriorates
Solution Approach 1:
The patent introduces olivine-coated particles specifically to address low-temperature performance, while the spinel layer handles voltage and stability requirements. This localized functional assignment allows the complex material composition to target specific performance gaps without unnecessary complexity elsewhere.
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrode material by incorporating olivine (LiFePO4) and spinel (LiNi0.8Mn0.1Co0.1O4) phases with specific crystal structures and electrochemical properties. These parameter changes enable low-temperature operation while managing the increased material complexity through controlled composition ratios.
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 active material design results in a rechargeable lithium battery with high energy density, high efficiency, and economic benefits by optimizing the charge and discharge efficiency, low-temperature properties, and lifetime characteristics.
Implementation Method 1
A rechargeable lithium battery is a battery including a positive electrode and a negative electrode containing active materials capable of intercalation and deintercalation of lithium ions
Implementation Method 2
A rechargeable lithium battery produces electrical energy through the oxidation and reduction reactions when lithium ions are intercalated into and deintercalated from the positive electrode and negative electrode
Data Source
AI summary
Disclosed are positive electrode active materials for a rechargeable battery, positive electrodes including the positive electrode active materials, and rechargeable lithium batteries including the positive electrode active materials. The positive electrode active material comprises first particles comprising a compound having an olivine structure, second particles comprising a compound having a spinel structure, and third particles. An amount of the third particles is about 0.5 parts by weight to about 1.5 parts by weight based on 100 parts by weight of the positive electrode active material.