LNMO Composite Oxide Coating for High-Voltage Cathode Stability
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Solution Overview
Problem
The high operating voltage of spinel type LiNi0.5Mn1.5O4 leads to compatibility issues with conventional electrolytic solutions, causing side reactions and interface deterioration, which hinders its practical application due to high impedance and corrosion, resulting in poor capacity exertion, energy density, and cycling stability in secondary batteries.
Innovation Solution
A lithium nickel manganese-containing composite oxide with a monocrystal or quasi-monocrystal morphology and spherical or spherical-like grain shape is developed, incorporating metal-doping elements like Mo, Nb, Ru, Te, Ta, Ce, and Yb, which reduces corrosion and impedance, and a cladding layer is applied to enhance structural stability and reduce manganese ion leaching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If spinel type LiNi0.5Mn1.5O4 is used as positive electrode active material, then high energy density is achieved, but compatibility with conventional electrolytic solutions deteriorates due to high operating voltage
Solution Approach 1:
A surface modification layer is introduced as an intermediary between the LiNi0.5Mn1.5O4 active material and the electrolytic solution. This modification layer (using compounds such as Li2SiO3, Li3PO4, Li2SiO2N, or their composite structures) acts as a protective barrier that prevents direct contact between the high-voltage active material and the electrolyte, thereby eliminating side reactions and interface deterioration while preserving the high energy density characteristics of the original material
2Productivity
If high operating voltage is used to achieve high energy density, then capacity exertion is improved, but corrosion of electrolytic solution and interface impedance increase
Solution Approach 1:
The surface modification layer serves as a protective intermediary that allows the high operating voltage to be maintained for high capacity exertion, while simultaneously blocking the harmful effects of corrosion and impedance increase. The modification layer creates a stable interface that prevents electrolyte decomposition and maintains low resistance throughout battery operation
Solution Approach 2:
The positive electrode active material is transformed into a composite structure consisting of the core LiNi0.5Mn1.5O4 material combined with a surface modification layer. This composite structure integrates the high energy density advantages of the original material with the protective properties of the modification layer, achieving both high capacity exertion and resistance to corrosion and impedance
3Ease of manufacture
If conventional electrolytic solutions are used with high voltage active material, then manufacturing simplicity is maintained, but side reactions occur causing interface deterioration
Solution Approach 1:
The surface modification is performed as a preliminary action during the manufacturing process, before the battery is assembled and put into service. The modification layer is formed on the active material particles through processes such as co-precipitation, hydrothermal treatment, or solid-state reaction, creating a pre-protected structure that prevents side reactions from occurring during subsequent battery operation without requiring complex post-manufacturing modifications
Data Source
AI summary
The present application provides a lithium nickel manganese-containing composite oxide, a preparation method thereof, and a positive electrode plate, a secondary battery and an electrical device. The lithium nickel manganese-containing composite oxide is a particle with a monocrystal morphology or a quasi-monocrystal morphology, the lithium nickel manganese-containing composite oxide has a spherical or spherical-like grain shape, and the lithium nickel manganese-containing composite oxide has a general formula of Li1+xNi0.5+yMzMn1.5−x−y−z−aAaO4−k, −0.2≤x≤0.5, −0.2≤y≤0.2, 0≤z≤0.2, 0<a≤0.2, 0≤k≤0.2, A includes one or more selected from Si, P and S, M includes one or more selected from a metal-doping element. The lithium nickel manganese-containing composite oxide provided in the present application may improve the capacity exertion, energy density and cycling life of the secondary battery.