Lithium Ion Battery Positive Electrode Material Optimization
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Solution Overview
Problem
Current lithium ion battery positive electrode active materials do not adequately meet the requirements for high capacity and rate characteristics, particularly in large-sized battery applications.
Innovation Solution
A positive electrode active material with a layer structure represented by the compositional formula Lix(NiyMe1-y)Oz, where Me includes metals like Mn, Co, Al, Mg, Cr, Ti, Fe, Nb, Cu, and Zr, with specific lattice constant and compositional ratio coordinates within defined regions on a graph, optimizing the lithium to metal ratio for improved battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional lithium-containing transition metal oxides are used as positive electrode active materials, then basic battery function is achieved, but high capacity and rate characteristics are insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional ratios of Li, Ni, and Me in the formula Lix(NiyMe1-y)Oz, and by controlling the lattice constant a within specific ranges (0.287-0.289 nm). This optimization of compositional parameters and structural parameters simultaneously achieves high capacity and excellent rate characteristics, resolving the contradiction between quantity of substance and reliability.
Solution Approach 2:
The patent uses composite materials by creating a complex oxide system Lix(NiyMe1-y)Oz where Me represents multiple possible metals (Mn, Co, Al, Mg, Cr, Ti, Fe, Nb, Cu, Zr). This composite approach combines the advantages of different metals to achieve both high capacity and good rate characteristics that single-metal oxides cannot provide alone.
2Reliability
If complex oxide formulations are used to improve battery characteristics, then capacity and cycle characteristics are enhanced, but material composition control becomes more complex
Solution Approach 1:
The patent simplifies the complex formulation problem by identifying specific parameter ranges: Li content x=0.9-1.2, Ni content y=0.5-0.6, and lattice constant a=0.287-0.289 nm. By focusing on these key parameters, the patent achieves good cycle characteristics while making the formulation process more controllable and less complex.
3Productivity
If lattice constant and compositional ratio are optimized within specific regions, then high capacity and rate characteristics are achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent addresses the precision requirement by providing specific target ranges: lattice constant a=0.287-0.289 nm and compositional ratio Li/M within defined regions. These quantified parameters give manufacturers clear control targets, making it feasible to achieve high productivity and rate characteristics through controlled parameter optimization.
Data Source
AI summary
The present invention provides a positive electrode active material for a lithium ion battery which has high capacity and good rate characteristics. The positive electrode active material has a layer structure represented by the compositional formula: Liα(NiβMe1-β)Oγ, wherein Me represents at least one type selected from the group consisting of Mn, Co, Al, Mg, Cr, Ti, Fe, Nb, Cu and Zr, x denotes a number from 0.9 to 1.2, y denotes a number from 0.5 to 0.65, and z denotes a number of 1.9 or more. The positive electrode active material is selected by measuring the coordinates of the lattice constant a and compositional ratio (Li/M) and selecting materials within the region enclosed by three lines given by the equations: y=−20.186x+59.079, y=35x−99.393, and y=−32.946x+95.78, wherein the x-axis represents a lattice constant a and the y-axis represents a compositional ratio (Li/M) of Li to M.