Cobalt-Free Layered Cathode Material with Uniform Bulk Doping
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Solution Overview
Problem
Current lithium-ion battery positive electrode materials face challenges such as high production costs, environmental impact from industrial wastewater, and structural instability due to the limitations of conventional synthesis methods like co-precipitation, which result in nonuniformity and inefficient doping of elements into the crystal lattice.
Innovation Solution
A method involving the mixing of lithium salt, nickel source, manganese source, and dopant with wet ball-milling and spray drying, followed by primary calcination in an oxygen-containing atmosphere, to produce a cobalt-free layered positive electrode material with specific chemical composition and doping elements like Ta, Rb, Sr, Zr, Na, Cs, Y, W, B, Nb, Ba, Mo, or P, enhancing structural stability and electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If co-precipitation method is used to synthesize precursor, then positive electrode material can be produced, but industrial wastewater is generated and production cost increases
Solution Approach 1:
The patent extracts and removes the harmful co-precipitation step from the synthesis process. Instead of using co-precipitation to create precursor, the invention directly synthesizes the layered positive electrode material through solid-state reaction of mixed oxides, thereby eliminating the generation of industrial wastewater associated with co-precipitation while maintaining manufacturability
Solution Approach 2:
The patent changes the synthesis approach from wet chemical co-precipitation to solid-state reaction. This parameter change involves transitioning from solution-based processing to direct solid material reaction, fundamentally altering the process to eliminate wastewater generation while achieving the desired product
2Ease of manufacture
If co-precipitation method is used to synthesize precursor, then positive electrode material can be produced, but production cost increases due to multiple process steps
Solution Approach 1:
The patent merges multiple separate process steps into a single integrated solid-state reaction process. Instead of separately performing co-precipitation, drying, mixing with lithium salt, and calcination, the invention combines these operations by directly reacting mixed metal oxides with lithium carbonate in one calcination step, thereby reducing process complexity and cost
Solution Approach 2:
The patent performs preliminary mixing of metal oxide precursors with lithium carbonate before the main reaction. This preliminary preparation ensures uniform distribution of reactants, allowing the subsequent single-step solid-state reaction to proceed efficiently without requiring intermediate co-precipitation and mixing steps
3Ease of manufacture
If co-precipitation method is used to synthesize precursor, then positive electrode material can be produced, but doping elements are not uniformly incorporated into crystal lattice
Solution Approach 1:
The patent performs preliminary mixing of all metal oxide components including dopant oxides with lithium carbonate before the main calcination reaction. This preliminary action ensures that dopant elements are uniformly distributed throughout the reactant mixture, which directly leads to uniform incorporation into the crystal lattice during the solid-state reaction, achieving high doping uniformity
4Reliability
If interface doping is used to stabilize structure, then positive electrode material can be synthesized, but structure stability attenuates quickly during cycling
Solution Approach 1:
The patent applies doping elements at multiple locations within the crystal structure - both at interfaces and within the bulk lattice. This multi-location doping approach provides localized structural stabilization at interfaces while simultaneously providing distributed stabilization throughout the bulk material, preventing the rapid attenuation of structure stability during cycling that occurs with interface doping alone
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 method reduces production costs, minimizes wastewater, achieves bulk phase doping, and improves the stability and electrochemical performance of the cobalt-free material, offering a cost-effective and environmentally friendly alternative to conventional methods.
Implementation Method 1
mixing a lithium salt, a nickel source, a manganese source, a dopant and a solvent, and then carrying out a wet ball-milling to obtain a mixed slurry
Implementation Method 2
spray drying the mixed slurry to obtain a precursor
Implementation Method 3
carrying out a primary calcination on the precursor in an oxygen-containing atmosphere to obtain the layered cobalt-free positive electrode material
Implementation Method 4
carrying out a primary calcination on the precursor in an oxygen-containing atmosphere
Data Source
AI summary
Provided is a preparation method for a layered cobalt-free positive electrode material, the method comprising the steps: (1) mixing a lithium salt, a nickel source, a manganese source, a dopant and a solvent, and subjecting same to wet ball milling to obtain a mixed slurry; (2) spray drying the mixed slurry to obtain a precursor; and (3) carrying out one instance of calcination on the precursor in an oxygen-containing atmosphere to obtain the layered cobalt-free positive electrode material. Further provided are a layered cobalt-free positive electrode material, which is obtained by the preparation method, and a lithium-ion battery containing the layered cobalt-free positive electrode material. In the preparation method, an expensive cobalt element is replaced with a specific type of doping element, and wet ball milling and spray drying processes are used cooperatively, such that not only bulk phase doping can be realized, but also, a c-axis increases, layering is more obvious, and lithium-nickel mixing is reduced when crystals are formed in the material, thereby improving the stability of the material, and excellent electrochemical performance is obtained.