Composite Cathode Material for Stable High-Capacity Li-Ion Batteries
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Solution Overview
Problem
Lithium-ion batteries face challenges with low gram capacity, fast early cycle attenuation, and poor structural stability due to issues with lithium manganese phosphate as a positive electrode active material, leading to decreased energy density and cycle life.
Innovation Solution
A positive electrode active material is formulated by mixing lithium manganese phosphate with a second active material that meets specific doping criteria, including ion radius and valence conditions, to enhance gram capacity, structural stability, and electronic conductivity, achieved through particle grading and doping elements like Zn, Al, Na, and others.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If lithium manganese phosphate is used as positive electrode active material, then structural stability is improved, but gram capacity decreases
Solution Approach 1:
The patent combines lithium manganese phosphate (providing structural stability) with a second positive electrode active material (providing high gram capacity) to form a composite positive electrode. This merging allows the electrode to simultaneously achieve both structural stability and high gram capacity, resolving the contradiction between these two parameters.
Solution Approach 2:
The patent creates a composite positive electrode material consisting of lithium manganese phosphate and another positive electrode active material. This composite structure leverages the advantages of both materials: the structural stability of lithium manganese phosphate and the high capacity of the second material, thereby resolving the contradiction between structural stability and gram capacity.
2Ease of manufacture
If lithium manganese phosphate is used as positive electrode active material, then manufacturing cost is reduced, but energy density decreases
Solution Approach 1:
The patent merges lithium manganese phosphate (low cost) with a second positive electrode active material (high energy density) to create a composite positive electrode. This combination allows the electrode to achieve both cost-effectiveness and high energy density, resolving the contradiction between manufacturing cost and energy density.
Solution Approach 2:
The patent develops a composite positive electrode material that integrates lithium manganese phosphate and another active material. This composite structure enables the electrode to maintain low manufacturing cost while achieving high energy density through the contribution of the second material, thus resolving the cost-energy density contradiction.
3Duration of action of stationary object
If lithium manganese phosphate is used as positive electrode active material, then cycle life is improved, but gram capacity is limited
Solution Approach 1:
The patent combines lithium manganese phosphate (providing long cycle life) with a second positive electrode active material (providing high gram capacity) to form a composite positive electrode. This merging enables the electrode to simultaneously achieve both long cycle life and high gram capacity, resolving the contradiction between these two parameters.
Solution Approach 2:
The patent creates a composite positive electrode material consisting of lithium manganese phosphate and another positive electrode active material. This composite structure leverages the advantages of both materials: the long cycle life of lithium manganese phosphate and the high capacity of the second material, thereby resolving the contradiction between cycle life and gram capacity.
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 mixed active material achieves higher gram capacity, improved structural stability, and increased energy density while reducing manufacturing costs, balancing better cycle life and energy density in lithium-ion batteries.
Implementation Method 1
the lithium manganese phosphate has a doping element satisfying at least one of the following conditions: the ion radius of the doping element and the ion radius of the manganese element satisfy that |a−b|/b is not greater than 10%
Data Source
AI summary
The positive electrode active material, a positive electrode slurry, a positive electrode plate, a battery, and an electrical apparatus are disclosed. The positive electrode active material includes a first positive electrode active material comprising lithium manganese phosphate and a second positive electrode active material different from the first. The lithium manganese phosphate contains a doping element that satisfies at least one of the following conditions: (i) the relative difference in ionic radius between the doping element and manganese is not greater than 10%; (ii) the valence variation voltage of the doping element is between 2 V and 5.5 V; (iii) the chemical bond activity between the doping element and oxygen is not less than that of the phosphorus-oxygen bond; and (iv) the highest valence of the doping element is not greater than 6.