Lithium Manganese Phosphate Doping for Capacity and Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries face challenges with low gram capacity, fast cycle attenuation, and poor structural stability due to the limitations of lithium manganese phosphate as a positive electrode active material, which results in 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 conductivity, achieved through particle grading and doping elements like Zn, Al, and Si.
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 uses a composite material system consisting of lithium manganese phosphate as the base material combined with specific doping elements (Ni, Co, Zn, Al, Si, Ti, V, Mo, W) to create a composite positive electrode active material. This composite structure allows the material to simultaneously achieve high structural stability from lithium manganese phosphate and high gram capacity (200-250 mAh/g) from the optimized composite composition, 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 cost is reduced, but energy density decreases
Solution Approach 1:
The patent optimizes multiple parameters of the lithium manganese phosphate material including doping element composition ratios, particle size distribution (Dv10, Dv50, Dv90 values), and sintering conditions to achieve a material with both cost-effectiveness and high energy density. By precisely controlling these parameters, the material achieves gram capacity of 200-250 mAh/g and discharge voltage plateau of 3.7-3.9V, thereby achieving high energy density while maintaining the cost advantages of lithium manganese phosphate.
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 applies local quality optimization by introducing doping elements at specific sites within the lithium manganese phosphate crystal structure. The doping elements are strategically positioned to locally enhance both the structural stability (improving cycle life) and the electrochemical activity (improving gram capacity). This localized modification allows the material to achieve both long cycle life and high gram capacity simultaneously.
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%, wherein a is the ionic radius of the doping element, and b is the ion radius of the manganese element; the valence variation voltage of the doping element is U, and 2V
Implementation Method 2
a first positive electrode active material comprising lithium manganese phosphate; a second positive electrode active material different from the first positive electrode active material
Data Source
Figure 1~3
Figure 4~6
AI summary
The present application discloses a positive electrode active material, a positive electrode slurry, a positive electrode plate, a battery, and an electrical apparatus, wherein the positive electrode active material comprises: a first positive electrode active material comprising lithium manganese phosphate; a second positive electrode active material different from the first positive electrode active material, wherein 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 manganese element satisfy that |a-b|/b is not greater than 10%, wherein a is the ionic radius of the doping element, and b is the ion radius of manganese element; the valence variation voltage of the doping element is U, and 2V<U<5.5V; the chemical activity of the chemical bond formed by the doping element and O is not less than the chemical activity of P-O bond; and the highest valence of the doping element is not greater than 6.