Layered Oxide Cathode Composition for High-Pressure Electrode Rolling
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Solution Overview
Problem
Existing lithium-ion battery cathode materials with layered structures suffer from low compressive strength, leading to fractures during electrode plate preparation and lithium ion deintercalation, resulting in poor cycle performance and safety issues.
Innovation Solution
A lithium-containing oxide cathode material with a specific compressive index and a preparation method involving a precursor with enhanced compressive strength, achieved through controlled sintering and doping with elements like Ti, Zr, and Nb, to improve the material's stability and electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high pressure rolling is applied during electrode plate preparation to increase electrode density, then volume energy density is improved, but cathode material with low strength is fractured or crushed, leading to increased contact area with electrolyte and deterioration of cycle performance
Solution Approach 1:
The patent changes the chemical composition parameters of the cathode material by doping with elements M1 and M2 (where M1, M2 are selected from Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, In, Sn, Sb, Te, Pb, B, Si, P, S, Se, Te, and their combinations). This compositional parameter change enhances the mechanical strength and structural stability of the cathode material, enabling it to withstand high pressure rolling during electrode fabrication without fracturing or crushing, thus resolving the contradiction between achieving high electrode density and maintaining material strength.
Solution Approach 2:
The patent creates a composite cathode material structure by incorporating multiple metal elements (Ni, Co, Mn) along with doping elements M1 and M2 in a layered oxide structure Li[Ni1-x-yCoxMnyM1aM2b]O2. This composite approach combines the high capacity characteristics of NCM materials with the structural stability provided by doping elements, resulting in a material that exhibits both high electrode density after pressing and sufficient mechanical strength to resist fracture during fabrication and cycling.
2Duration of action of moving object
If repeated Li+ deintercalation is performed during battery use, then electrochemical cycling is achieved, but volume expansion or contraction of layered structure causes pulverization of low-strength cathode material, resulting in insufficient contact between particles and continuous formation of new electrolyte layers
Solution Approach 1:
The patent modifies the structural parameters of the cathode material through doping with elements M1 and M2, which stabilize the layered structure during Li+ deintercalation cycles. The doping elements adjust the lattice parameters and strengthen the crystal structure, preventing volume expansion or contraction that would otherwise cause pulverization. This enables the material to maintain particle integrity and contact over extended cycling, resolving the contradiction between achieving long cycle life and maintaining material strength during electrochemical operation.
3Ease of manufacture
If cathode material with low strength is used, then manufacturing simplicity is maintained, but the material is fractured or crushed during preparation process, increasing contact area and side reactions with electrolyte
Solution Approach 1:
The patent changes the compositional parameters of the cathode material by incorporating doping elements M1 and M2 in controlled amounts (where a+b represents the total doping content). This compositional modification enhances the mechanical strength and structural stability of the material, preventing fracture and crushing during the high pressure rolling process. The doped material maintains particle integrity, reduces contact area with electrolyte, and minimizes side reactions, thereby improving cycle performance while remaining compatible with existing manufacturing processes.
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 proposed solution results in a cathode material with improved compressive strength, stability, and electrochemical performance, including enhanced cycle life, rate performance, and safety, effectively addressing the limitations of existing materials.
Implementation Method 1
performing a first sintering in an atmosphere furnace, to obtain a primary sintered material
Implementation Method 2
performing a second sintering on the mixed material in an atmosphere furnace
Data Source
AI summary
The present invention relates to the technical field of lithium-ion batteries, and discloses a precursor of a lithium-containing oxide cathode material, a lithium-containing oxide cathode material, a preparation method and use thereof, and a positive electrode plate and use thereof. The cathode material has a compressive index Δλ(P100) satisfying Δλ(P100)≥60%+(y/x)×5%, where y/x is a molar ratio of Mn/Ni in the cathode material. The lithium-containing oxide cathode material has high compressive strength and stability, only a small degree of fracture occurs under high pressure during a preparation process of the electrode plate, and it can be continuously subjected to lithium ion deintercalation/deintercalation reactions without serious rupture.