Monocrystal High-Nickel Cathode Material With Low Residual Alkali
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Solution Overview
Problem
High-nickel ternary materials for lithium ion batteries face challenges with increasing surface residual alkali content and deteriorating cycle stability, especially when nickel content reaches 90 mol % or higher, leading to irreversible changes in material structure and increased production costs.
Innovation Solution
A modified monocrystal high-nickel ternary material is prepared through a method involving pre-sintering of a high-nickel ternary hydroxide precursor, followed by mixing with lithium hydroxide, nano-dopants, and alumina pellets, and subsequent high-temperature sintering in a pure oxygen atmosphere, which reduces residual alkali content and enhances structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If water washing method is used to reduce surface residual alkali content, then residual alkali content is reduced, but material structure undergoes irreversible changes and production cost increases significantly
Solution Approach 1:
The patent changes the processing parameters by using dry mixing and sintering instead of water washing. Specifically, the mixture is sintered at 900-1100℃ for 10-20 hours, which transforms the residual alkali through thermal treatment rather than chemical washing, thereby reducing residual alkali content while preserving the monocrystal structure
Solution Approach 2:
The patent replaces the chemical washing mechanism with a thermal-mechanical sintering process. The dry mixing followed by high-temperature sintering in a sintering furnace substitutes the water-based chemical removal process, eliminating the need for water washing while achieving similar or better results in reducing residual alkali
2Object-generated harmful factors
If water washing method is used to reduce surface residual alkali content, then residual alkali content is reduced, but production cost increases significantly
Solution Approach 1:
The patent merges the residual alkali reduction step with the main sintering process. By incorporating the alkali removal treatment into the 900-1100℃ sintering step that is already required for forming the monocrystal structure, the process eliminates the need for separate water washing steps, thereby reducing production cost while achieving the desired residual alkali content
Solution Approach 2:
The sintering process itself serves dual purposes: forming the monocrystal structure and reducing residual alkali content. The high-temperature treatment naturally volatilizes or transforms the residual alkali without requiring additional reagents or processing steps, making the system self-sufficient and cost-effective
3Quantity of substance
If nickel content is increased to achieve higher capacity, then battery capacity increases, but cycle stability deteriorates
Solution Approach 1:
The patent changes the compositional parameters by precisely controlling the nickel content to be 0.90-0.96 and incorporating specific amounts of cobalt (0.02-0.08) and manganese (0.02-0.08). This optimized composition ratio, combined with the extended sintering time of 10-20 hours, stabilizes the high-nickel structure and improves cycle stability while maintaining high capacity
Solution Approach 2:
The patent creates a composite ternary material LiNixCoyMn(1-x-y)O2 that combines nickel, cobalt, and manganese in specific ratios. The cobalt and manganese components stabilize the crystal structure of the high-nickel material, preventing degradation during cycling while maintaining the high capacity benefits of elevated nickel content
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 significantly reduces residual alkali content, eliminates the need for water washing, and lowers production costs, while maintaining the high energy density and cycle stability required for lithium ion batteries.
Implementation Method 1
pre-sintering a high-nickel ternary hydroxide precursor under a condition of pure oxygen to obtain a pre-sintered material
Implementation Method 2
pre-sintering a high-nickel ternary hydroxide precursor under a condition of pure oxygen
Implementation Method 3
subjecting a mixture to a first sintering in a pure oxygen atmosphere
Implementation Method 4
subjecting a mixture to a first sintering in a pure oxygen atmosphere
Implementation Method 5
subjecting a mixed material to a second sintering in a pure oxygen atmosphere to obtain a second sintered material
Data Source
AI summary
The present disclosure provides a modified monocrystal high-nickel ternary material, a preparation method therefor and use thereof. The preparation method includes: pre-sintering a high-nickel ternary hydroxide precursor under a condition of pure oxygen to obtain a pre-sintered material; fully mixing the pre-sintered material with a micro-powder of lithium hydroxide, a nano-dopant and an alumina pellet, and subjecting a mixture to a first sintering in a pure oxygen atmosphere after the alumina pellet is removed by sieving, followed by natural cooling in a pure oxygen atmosphere after the first sintering is completed to obtain a first sintered material; crushing the first sintered material, fully mixing it with a nano-coating agent, and then subjecting a mixed material to a second sintering in a pure oxygen atmosphere to obtain a second sintered material; and subjecting the second sintered material to crushing, sieving and demagnetizing to obtain the modified monocrystal high-nickel ternary material.