Hetero-Doped Cathode Material for High-Voltage Stability
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Solution Overview
Problem
Lithium secondary batteries face challenges with cathode active materials such as LiCoO2 due to safety concerns and high costs, while LiNiO2 suffers from high production costs, gas generation, and low chemical stability, and LiMn2O4 has lower energy density, necessitating a material with improved high-speed charging characteristics and lifespan.
Innovation Solution
A cathode active material incorporating lithium transition metal oxides with hetero elements like Ti, Co, Al, Cu, Fe, Mg, B, Cr, Bi, and Zr at the surface and inside, which suppress manganese elution and gas generation under high voltage, enhancing structural stability and charge/discharge efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If LiCoO2 is used as cathode active material, then excellent cycle properties are achieved, but safety is low and cost is high
Solution Approach 1:
The patent uses a composite cathode active material comprising LiCoO2 combined with LiMn2O4 and surface-modified with hetero elements. This composite structure leverages the excellent cycle properties of LiCoO2 while incorporating Mn to improve safety and reduce cost, resolving the contradiction between cycle life and safety/reliability
2Quantity of substance
If LiNiO2 is used as cathode active material, then high discharge capacity is achieved, but chemical stability is low and gas generation occurs
Solution Approach 1:
The patent applies surface modification with hetero elements (Al, Mg, Ti, Zr, etc.) specifically on the surface of the LiNiO2 particles. This local quality change stabilizes the surface chemistry, preventing gas generation and improving chemical stability while maintaining the high discharge capacity of the bulk LiNiO2 material
3Power
If LiMn2O4 is used as cathode active material, then cost is reduced and output is improved, but energy density is lower
Solution Approach 1:
The patent merges LiMn2O4 with LiCoO2 in a composite structure, combining the cost advantages and high output characteristics of LiMn2O4 with the high energy density capabilities of LiCoO2. The hetero element surface modification further enhances this synergy by improving overall battery performance and stability
4Power
If high charge and discharge voltage potential is achieved, then energy performance is improved, but Mn dissolution increases and electrolyte side reactions occur
Solution Approach 1:
The hetero elements (Al, Mg, Ti, Zr, etc.) serve as intermediary protective layers on the surface of the cathode active material. These intermediaries prevent direct contact between the high-voltage material and the electrolyte, reducing Mn dissolution and side reactions while allowing the material to maintain its high voltage potential for improved energy performance
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 material exhibits excellent high-speed charge characteristics and extended lifespan, preventing structural collapse and decomposition under high voltage, thus improving battery performance and efficiency.
Implementation Method 1
at least one hetero element selected from the group consisting of Ti, Co, Al, Cu, Fe, Mg, B, Cr, Bi, Zn and Zr locates at a surface portion of or inside the lithium transition metal oxide
Data Source
AI summary
Disclosed are a cathode active material including a lithium transition metal oxide based on at least one transition metal selected from the group consisting of Ni, Mn and Co, wherein at least one hetero element selected from the group consisting of Ti, Co, Al, Cu, Fe, Mg, B, Cr, Bi, Zn and Zr is located at a surface portion of or inside the lithium transition metal oxide, and a secondary battery including the same. The cathode active material according to the present invention includes predetermined hetero elements at a surface thereof and therein, and, as such, a secondary battery based on the cathode active material may exhibit excellent high-speed charge characteristics and lifespan characteristics.