Doped NCM Cathode Material for High-Temperature Cycle Stability
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Solution Overview
Problem
Lithium-ion secondary batteries using lithium nickel cobalt manganese oxide as a positive electrode active material face challenges in achieving both high energy density and good high-temperature cycle performance.
Innovation Solution
A positive electrode active material with a lithium nickel cobalt manganese oxide composition having a layered crystal structure and controlled doping elements, ensuring a relative deviation of 20% or less in local mass concentration, exhibits an initial exothermic temperature of 200°C or more and an integral area of 100 J/g or less in a 78% delithiated state, enhancing thermal stability and high-temperature cycle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium nickel cobalt manganese oxide with high nickel content is used as positive electrode active material, then energy density is improved, but high-temperature cycle performance deteriorates
Solution Approach 1:
The patent applies local quality by introducing doping elements (such as Al, Si, Ti, V, Ge, Se, Zr, Nb, Ru, Pd, Sb, Te, or W) at specific locations within the lithium nickel cobalt manganese oxide crystal structure, specifically in the transition metal layer. This localized modification allows the bulk material to maintain high nickel content for energy density while the doped regions provide structural stability and thermal resistance, thereby improving high-temperature cycle performance without sacrificing energy density.
Solution Approach 2:
The patent creates a composite material system by combining lithium nickel cobalt manganese oxide with doping elements to form a heterogeneous structure. The base material provides high capacity and energy density, while the dopant phases provide structural reinforcement and thermal stability. This composite approach enables the simultaneous achievement of high energy density and improved high-temperature cycle performance by leveraging the complementary properties of different materials within the same electrode structure.
2Temperature
If doping elements are added to lithium nickel cobalt manganese oxide, then thermal stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by optimizing the doping concentration to be within 0.01-0.10 mol ratio, which is a carefully controlled parameter range. This specific doping level ensures sufficient thermal stability improvement while avoiding excessive doping that would cause aggregation and manufacturing difficulties. The patent also controls the relative deviation of local mass concentration to be 20% or less, establishing quantitative parameters that balance thermal performance with manufacturing feasibility.
Solution Approach 2:
The patent employs partial action by using relatively low doping concentrations (0.01-0.10 mol ratio) rather than high concentrations. This partial doping approach provides sufficient thermal stability enhancement while minimizing the risk of doping element aggregation and maintaining good manufacturing uniformity. The moderate doping level avoids excessive modification that would complicate the manufacturing process and reduce production precision.
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 enables lithium-ion secondary batteries to achieve higher energy density and improved high-temperature cycle performance by maintaining structural integrity and inhibiting irreversible phase transitions, thereby enhancing thermal stability and cycle stability.
Implementation Method 1
a transition metal layer of the lithium nickel cobalt manganese oxide includes a doping element
Implementation Method 2
the lithium nickel cobalt manganese oxide has a layered crystal structure with space group R3m
Implementation Method 3
the electrochemical lithiation/delithiation process in the anode material for lithium ion batteries
Implementation Method 4
Lithium-ion secondary battery is a kind of rechargeable battery, which mainly relies on the movement of lithium ions between the positive electrode and the negative electrode to work
Implementation Method 5
in a differential scanning calorimetry spectrum of the positive electrode active material in a 78% delithiated state, an initial exothermic temperature of a main exothermic peak is 200°C or more
Data Source
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AI summary
The present application discloses a positive electrode active material and a preparation method thereof, a positive electrode plate, a lithium-ion secondary battery and a battery module, a battery pack and an apparatus related thereto. The positive electrode active material includes a lithium nickel cobalt manganese oxide, the molar content of nickel in the lithium nickel cobalt manganese oxide accounts for 60% - 90% of the total molar content of nickel, cobalt and manganese, and the lithium nickel cobalt manganese oxide has a layered crystal structure of a space group R 3m; a transition metal layer of the lithium nickel cobalt manganese oxide includes a doping element, and the local mass concentration of the doping element in particles of the positive electrode active material has a relative deviation of 20% or less; and in a differential scanning calorimetry spectrum of the positive electrode active material in a 78% delithiation state, an initial exothermic temperature of a main exothermic peak is 200°C or more, and an integral area of the main exothermic peak is 100 J/g or less.