Core-Shell Lithium Manganese Phosphate Cathode for Faster Li-Ion Transport
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium manganese phosphate positive electrode active materials in lithium-ion secondary batteries exhibit poor rate performance, limiting their commercial application despite advantages in capacity and safety.
Innovation Solution
A positive electrode active material with a core of chemical formula LiaAxMn1-yByP1-zCzO4-nDn enveloped by a doped carbon shell layer, where A, B, C, and D elements are strategically doped to improve rate performance, cycling stability, and high-temperature stability, and the doping elements such as nitrogen, phosphorus, sulfur, boron, or fluorine are used to enhance lithium ion transport and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium manganese phosphate is used as positive electrode active material, then high capacity and good safety are achieved, but poor rate performance occurs
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core maintains the original lithium manganese phosphate composition for high capacity, while the shell layer is doped with carbon and specific elements (N, P, S, B, F) to enhance electrical conductivity and lithium ion transport. This localized modification at the surface level improves rate performance without compromising the bulk material's high capacity characteristics.
Solution Approach 2:
The patent employs composite materials by combining lithium manganese phosphate with a doped carbon shell layer containing multiple doping elements. The composite structure integrates the high capacity of lithium manganese phosphate with the enhanced conductivity and ion transport properties of the doped carbon shell, achieving both high capacity and improved rate performance simultaneously.
2Quantity of substance
If lithium manganese phosphate is used as positive electrode active material, then high capacity is achieved, but poor cycling performance occurs
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core maintains the original lithium manganese phosphate composition for high capacity, while the shell layer is doped with carbon and specific elements (N, P, S, B, F) to enhance electrical conductivity and lithium ion transport. This localized modification at the surface level improves rate performance without compromising the bulk material's high capacity characteristics.
Solution Approach 2:
The patent employs composite materials by combining lithium manganese phosphate with a doped carbon shell layer containing multiple doping elements. The composite structure integrates the high capacity of lithium manganese phosphate with the enhanced conductivity and ion transport properties of the doped carbon shell, achieving both high capacity and improved rate performance simultaneously.
3Quantity of substance
If lithium manganese phosphate is used as positive electrode active material, then high capacity is achieved, but poor high-temperature stability occurs
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core maintains the original lithium manganese phosphate composition for high capacity, while the shell layer is doped with carbon and specific elements (N, P, S, B, F) to enhance electrical conductivity and lithium ion transport. This localized modification at the surface level improves rate performance without compromising the bulk material's high capacity characteristics.
Solution Approach 2:
The patent employs composite materials by combining lithium manganese phosphate with a doped carbon shell layer containing multiple doping elements. The composite structure integrates the high capacity of lithium manganese phosphate with the enhanced conductivity and ion transport properties of the doped carbon shell, achieving both high capacity and improved rate performance 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 solution significantly improves rate performance, cycling stability, and high-temperature stability, while reducing Mn dissolution and increasing the compacted density of the material, thereby enhancing the overall performance of lithium-ion secondary batteries.
Implementation Method 1
the doping element atoms create a defect structure within the carbon material, facilitating the rapid migration of lithium ions
Implementation Method 2
introducing doping element atoms into the shell layer alters the charge distribution around carbon atoms, improving the electrical conductivity of the shell layer
Data Source
AI summary
Provided are a positive electrode active material and a preparation method thereof, a positive electrode plate, a secondary battery, a battery module, a battery pack, and an electric apparatus. The positive electrode active material includes a core and a shell layer enveloping the core, the core having a chemical formula LiaAxMn1-yByP1-zCzO4-nDn, where A includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W, B includes one or more elements selected from Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, C includes one or more elements selected from B, S, Si, and N, and D includes one or more elements selected from S, F, Cl, and Br; and the shell layer is a doped carbon layer, a doping element in the doped carbon layer including any one or more selected from nitrogen, phosphorus, sulfur, boron, and fluorine.