Layered Cathode Composition With Expanded TM Spacing for Lower Resistance
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Solution Overview
Problem
Conventional positive electrode active materials face challenges in incorporating specific additive elements into their crystal structures, hindering the improvement of battery resistance characteristics in lithium-ion batteries.
Innovation Solution
A positive electrode active material with a composition of Li x Ni a Co b Mn c M1 d M2 O 2 and a TM interlayer distance (D) of 2.02 Å to 2.30 Å, where M1 and M2 elements are combined to facilitate their incorporation into the crystal structure, stabilizing the structure and inhibiting Ni-mixing during charging and discharging, thereby reducing battery resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If specific additive elements are added to positive electrode active materials to improve battery resistance characteristics, then battery resistance characteristics are improved, but the additive elements have difficulty getting into the crystal structures of the positive electrode active materials
Solution Approach 1:
The patent changes the crystal structure parameters by expanding the TM interlayer distance to 2.02-2.30 Å through specific doping with M1 and M2 elements. This parameter change creates a more open crystal structure that facilitates the incorporation of additive elements while maintaining structural stability, thereby resolving the contradiction between improving battery resistance characteristics and enabling easy incorporation of additive elements.
Solution Approach 2:
The patent creates a composite doped oxide structure by combining multiple elements (Ni, Co, Mn, M1, M2, Li) in specific ratios within the crystal lattice. This composite approach allows different elements to occupy specific sites and contribute different functions: Ni for capacity, Co and Mn for stability, and M1/M2 for resistance improvement, while the expanded interlayer distance accommodates all components effectively.
2Ease of manufacture
If the TM interlayer distance is increased to facilitate additive element incorporation, then additive elements can be incorporated more easily, but the crystal structure stability may be compromised
Solution Approach 1:
The patent optimizes the TM interlayer distance parameter to a specific range (2.02-2.30 Å) that balances two competing requirements: it is expanded enough to accommodate additive elements M1 and M2, yet not so expanded as to compromise the overall crystal structure stability. This precise parameter control allows simultaneous achievement of easy element incorporation and structural stability.
Solution Approach 2:
The patent applies local quality by having different elements occupy specific crystallographic sites with different functions. M1 and M2 elements are incorporated at specific doping sites to expand the interlayer distance locally where needed for resistance improvement, while the overall layered structure maintains its stability. The Ni, Co, and Mn elements remain in their respective octahedral sites maintaining structural integrity.
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 combined M1 and M2 elements effectively increase the TM interlayer distance, stabilizing the crystal structure and reducing battery resistance, leading to improved battery performance.
Implementation Method 1
the nickel-cobalt-manganese-based lithium transition metal oxide is doped with a doping element M1 (where the doping element M1 is a metal element including Al) and a doping element M2
Implementation Method 2
a sintering step of sintering the mixture by heating it in an oxygen atmosphere to a maximum attained temperature X - 100°C
Data Source
AI summary
A positive electrode active material has a composition represented by LixNiaCObMncM1dM2eO2 and a TM interlayer distance (D) of 2.02 Å to 2.30 Å. In the composition, 0.1 ≤ x ≤ 1.5, 0.5 ≤ a ≤ 1.0, 0 ≤ b ≤ 0.3, 0 ≤ c ≤ 0.3, a + b + c = 1.0, 0.0005 ≤ d ≤ 0.050, and 0.0005 ≤ e ≤ 0.050, M1 represents at least one type of element selected from the group comprising Ba, Pr, La, Y, Sr, Ce, Se, Hf, Rh, Zr, and Sn, and M2 represents at least one type of element selected from the group comprising W, Re, Sb, Sn, Ta, Os, Ir, Mo, Nb, Tc, Ru, Ga, Ag, Pd, Ge, As, Zr, In, Pt, Al, and Ti.