Hybrid Positive Electrode Material for Lithium-Ion Battery Energy Density
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Solution Overview
Problem
Current lithium ion batteries face challenges in balancing energy density and safety performance, particularly with materials like LiFePO4 and ternary compounds, which struggle with storage performance and safety during high-temperature conditions, making them unsuitable for large-scale production.
Innovation Solution
A positive active material for lithium ion batteries is developed, comprising a combination of first and second lithium transition metal oxides with specific compositions and weight ratios, optimized for compacted density and particle size to enhance energy density and stability, including Li a (Ni b Co c Mn d ) 1-e M e O 2 and Li x Ni y Co z M" s O 2, with a 50:50 to 80:20 weight ratio, and using specific elements like Al, Mg, Ti, and Mn to improve thermal stability and cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LiNi0.8Co0.1Mn0.1O2 is used as positive electrode material to achieve high energy density, then the energy density is improved, but the storage performance and safety performance deteriorate
Solution Approach 1:
The patent divides the positive electrode material into two distinct components: a first lithium transition metal oxide (LiFePO4) providing safety and stability, and a second lithium transition metal oxide (LiNi0.8Co0.1Mn0.1O2) providing high energy density. This segmentation allows each material to fulfill its specific function without compromising the other, resolving the contradiction between energy density and safety performance
Solution Approach 2:
The patent creates a composite positive electrode material by combining LiFePO4 and LiNi0.8Co0.1Mn0.1O2 in a specific weight ratio range (30:70 to 70:30). This composite structure integrates the thermal stability and safety of LiFePO4 with the high energy density of LiNi0.8Co0.1Mn0.1O2, achieving both high energy density and improved storage/safety performance simultaneously
2Reliability
If LiFePO4 is used as positive electrode material to improve storage performance and safety, then the safety performance is improved, but the energy density deteriorates
Solution Approach 1:
The patent merges LiFePO4 (providing safety and storage performance) with LiNi0.8Co0.1Mn0.1O2 (providing high energy density) into a single composite positive electrode material. By combining these two materials in optimized weight ratios, the patent achieves both safety performance improvement and high energy density, resolving the contradiction between safety and energy density
3Reliability
If the weight ratio of first lithium transition metal oxide to second lithium transition metal oxide is increased to improve safety, then the safety performance is improved, but the energy density deteriorates
Solution Approach 1:
The patent optimizes the weight ratio parameter of the composite material, specifying a range of 30:70 to 70:30 (first to second lithium transition metal oxide). This parameter optimization allows flexible adjustment between safety and energy density based on application requirements, while maintaining both performance aspects within the optimal range, resolving the contradiction through parameter tuning
Data Source
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AI summary
The present invention provides a positive electrode active material includes a first lithium transition metal oxide represented by formula Lia(NibCocMnd)1-eMeO2 or Lia(NibCocAld)1-eM'eO2, wherein 0.9<a<1.1, 0.6≤b<0.9, 0.1≤c<0.4, 0.05<d<0.4, 0≤e≤0.1, b+c+d=1, M is at least one of Al, Mg, Ti, Zr, M' is at least one of Mg, Ti, Zr, and a second lithium transition metal oxide represented by formula LixNiyCozM"sO2, wherein 0.9<x<1.1, 0.4≤y<0.6, 0.2≤z<0.5, 0.2≤s<0.5, y+z+s=l, M"is at least one of Mn, Al, Mg, Ti, Zr, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Nb, Mo, Sr, Sb, W, Bi. The positive electrode active material for a lithium ion battery of the present invention shows a high compacted density. The present invention also provides a lithium ion battery using the positive electrode active material of the present invention. The lithium ion battery has high gram capacity, high energy density, good storage performance, and good cycle stability.