Lithium Nickel Manganese Cobalt Oxide Cathode Precursor
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Solution Overview
Problem
Current lithium-ion battery cathode materials, particularly LiCoO2-based ones, are expensive and have limited capacity, while alternatives like LNMCO face challenges with thermal stability and capacity loss, necessitating improved precursors for enhanced performance and cost-effectiveness, especially for automotive applications which require high cycle stability and low irreversible capacity.
Innovation Solution
Development of particulate precursor compounds with specific surface area and sulfur content ratios for lithium transition metal oxides, prepared using a loop reactor process, to produce cathode materials with reduced irreversible capacity and improved direct current resistance, suitable for both electric vehicles and hybrid electric vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LiCoO2-based cathode materials are used, then high energy density is achieved, but high cost and low capacity are problems
Solution Approach 1:
The patent uses composite LNMCO materials combining lithium, nickel, manganese, cobalt, and oxygen in specific ratios to achieve both high energy density and high capacity. The composite structure allows synergistic effects where nickel provides capacity, cobalt provides stability, and manganese provides structural support, resolving the contradiction between energy density and capacity.
Solution Approach 2:
The patent optimizes the stoichiometric parameters of the LNMCO composition (Li1+xM1-xO2 where M=NixCoyMnzAm) by adjusting the ratios of nickel, cobalt, manganese and dopant elements. By changing these compositional parameters within specific ranges, the material achieves both high energy density and high capacity simultaneously, overcoming the limitations of pure LiCoO2.
2Quantity of substance
If LNMCO cathode materials are used to reduce cost and increase capacity, then raw material price decreases, but thermal stability decreases with increasing Ni content
Solution Approach 1:
The patent applies local quality by strategically distributing different elements within the LNMCO structure. Nickel is positioned to provide capacity in specific crystallographic sites, while cobalt and manganese are distributed to provide thermal stability in other regions. The dopant elements (Al, Mg, Zr, Ti, Sn, Fe) are locally incorporated to stabilize specific structural regions, allowing high nickel content for capacity while maintaining overall thermal stability.
Solution Approach 2:
The composite LNMCO material combines multiple elements with complementary properties: nickel for capacity, cobalt for electrochemical stability, manganese for structural stability, and dopant elements for enhanced thermal stability. This composite approach allows the material to achieve high capacity through nickel while the other elements provide the necessary thermal stability, resolving the contradiction between capacity and thermal stability.
3Stability of the object's composition
If Mn is added as structural stabilizing element to compensate for decreasing thermal stability, then thermal stability is improved, but capacity is lost
Solution Approach 1:
The patent merges the functions of multiple elements within the LNMCO structure. Nickel provides capacity, cobalt provides electrochemical stability, and manganese provides structural stability. By combining these elements in specific ratios within the same crystal structure, the material achieves both high capacity (from nickel) and high thermal stability (from manganese), resolving the contradiction between capacity and thermal stability that exists when elements are used separately.
4Quantity of substance
If high surface area nanostructured lithium layered oxides are used, then discharge capacity is improved, but surface reactivity increases leading to side reactions and destabilization
Solution Approach 1:
The LNMCO composite material provides a balanced surface chemistry that reduces excessive reactivity. The presence of cobalt and manganese alongside nickel creates a more stable surface composition that is less prone to side reactions with the electrolyte, even at high surface areas. The dopant elements further stabilize the surface structure, allowing high surface area nanostructuring for improved discharge capacity while maintaining electrolyte safety and preventing destabilization.
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 approach results in lithium-ion battery cathode materials with reduced irreversible capacity and enhanced direct current resistance, addressing the cost and performance limitations of existing materials, thereby improving battery longevity and efficiency for automotive applications.
Implementation Method 1
The precipitation typically takes place in a continuous stirred tank reactor (a CSTR reactor). For characterizing a secondary lithium cell one of the most important parameters besides the discharge capacity is the irreversible capacity
Implementation Method 2
the cathode precursors need to contain the transition metal in a well-mixed form (at atomic level) as provided in mixed transition metal hydroxides, carbonates etc. Mixed hydroxides or carbonates are typically prepared by precipitation reactions
Data Source
AI summary
A particulate precursor compound for manufacturing a lithium transition metal (M)-oxide powder for use as an active positive electrode material in lithium-ion batteries, wherein (M) is NixMnyCozAv, A being a dopant, wherein 0.33≤x≤0.60, 0.20≤y≤0.33, and 0.20≤z≤0.33, v≤0.05, and x+y+z+v=1, the precursor comprising Ni, Mn and Co in a molar ratio x:y:z and having a specific surface area BET in m2/g and a sulfur content S expressed in wt %, wherein formula (I).