Molten-Salt Ternary Cathode Synthesis for Stable Cycling
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Solution Overview
Problem
Current methods for synthesizing cathode materials for lithium-ion batteries, such as high-temperature solid-phase, sol-gel, and co-precipitation methods, are energy-intensive, time-consuming, and introduce impurities, while the molten-salt method lacks studies on high-performance ternary cathode material preparation.
Innovation Solution
A method involving mixing nickel, cobalt, and manganese salts with a metal oxide and acid, followed by reaction with sodium hydroxide and ammonia, then ball-milling with a lithium source and molten salt, and subsequent sintering and annealing to produce a ternary cathode material with enhanced crystallinity and lattice porosity, which buffers volume expansion and improves cycling stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature solid-phase method is used, then cathode material can be synthesized, but long roasting time and high energy consumption are required
Solution Approach 1:
The patent changes the physical state parameter of the reaction medium from solid phase to liquid phase (molten salt), enabling the reaction to proceed at lower temperatures (800-900°C instead of higher temperatures) and shorter times, thus reducing energy consumption while maintaining synthesis reliability
Solution Approach 2:
The patent introduces molten salt as an intermediary medium that facilitates the reaction between nickel, cobalt, and manganese salts. The molten salt acts as both solvent and lithium source, enabling atomic-scale contact and high diffusion rates, which reduces roasting time and energy consumption compared to traditional solid-phase methods
2Reliability
If high-temperature solid-phase method is used, then cathode material can be synthesized, but long roasting time is required
Solution Approach 1:
The patent changes the reaction medium from solid to liquid (molten salt), which increases atomic mobility and diffusion rates, reducing the roasting time from hours to minutes while maintaining complete reaction and material quality
Solution Approach 2:
Molten salt serves as an intermediary that enables rapid mass transport and atomic-scale mixing of reactants. The liquid phase allows ions to move freely and react quickly, dramatically reducing the time required for complete synthesis compared to solid-state diffusion
3Reliability
If sol-gel method is used, then cathode material can be synthesized, but solvent evaporation causes additional material and energy consumption
Solution Approach 1:
The patent uses molten salt as an intermediary medium that remains in the system during reaction and serves dual purposes: as solvent for reactant dissolution and as lithium source for product formation. This eliminates the need for separate solvent evaporation steps and associated material losses
Solution Approach 2:
The molten salt performs multiple functions simultaneously: it acts as solvent, lithium source, and reaction medium. This multi-functionality eliminates the need for separate solvent removal steps, reducing both time and material consumption compared to sol-gel methods
4Reliability
If co-precipitation method is used, then cathode material can be synthesized, but complicated synthesis steps and time consumption are required
Solution Approach 1:
The patent combines multiple steps into one: mixing nickel, cobalt, and manganese salts with the molten salt simultaneously achieves dissolution, mixing, and lithium source incorporation. This single-step approach replaces the multiple separate steps required in co-precipitation methods, simplifying the process while maintaining product quality
5Manufacturing precision
If spray-drying method is used, then nanoscale primary particles can be synthesized, but expensive equipment is required
Solution Approach 1:
The patent changes the particle formation mechanism from spray-drying (requiring specialized equipment) to molten salt-assisted sintering. The molten salt enables atomic-scale mixing and controlled particle growth during sintering, achieving uniform nanoscale particles through chemical control rather than mechanical spray processes
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 method produces a ternary cathode material with improved cycling stability and specific capacity by creating atomic vacancies in the lattice and forming a coating layer, enhancing the material's performance in lithium-ion batteries.
Implementation Method 1
reactants have a high diffusion rate in a molten salt, for example, an ion migration rate is in a range from 1×10−5 to 1×10−8 cm2/s in a molten salt
Implementation Method 2
A molten salt is mainly used as a solvent and a diffusion medium during the entire reaction process
Implementation Method 3
mixing the precursor, a lithium source and a molten salt, and subjecting a resulting mixture to ball-milling
Implementation Method 4
subjecting a resulting mixture to ball-milling and then to sintering in an oxygen atmosphere to obtain a sintered material
Implementation Method 5
sintering in an oxygen atmosphere
Implementation Method 6
subjecting the sintered material to water-washing, drying and annealing to obtain the ternary cathode material
Data Source
AI summary
The present disclosure discloses a method for preparing a ternary cathode material with a molten salt and use thereof. The method includes: mixing a nickel salt, a cobalt salt, a manganese salt, a metal oxide and an acid liquor to obtain a mixed salt solution; concurrently adding the mixed salt solution, a sodium hydroxide solution and ammonia water to a base solution to allow a reaction to obtain a precursor; and mixing the precursor, a lithium source and a molten salt, and subjecting a resulting mixture to sintering, water-washing and annealing to obtain the ternary cathode material. In the present disclosure, a bismuth/antimony-doped ternary precursor is prepared, which is sintered with a molten salt, during which bismuth/antimony oxide is melted in the molten salt, then a resulting mixture is washed with water, and annealed to form a coating layer on a surface of the material.