Lithium-Rich Manganese Cathode with Dual-Particle Capacity Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-rich manganese-based laminated positive electrode materials suffer from severe capacity and voltage decay during long cycles, exhibiting poor long-cycle stability due to irreversible capacity loss and decreased ionic/electronic conductivity.
Innovation Solution
A lithium-rich manganese-based positive electrode material composed of first and second particles, where the first particle has a lower Li2O/Li2MnO3 component and a specific lithium-oxygen ratio (R_A), and the second particle has a higher Li2O/Li2MnO3 component and a different lithium-oxygen ratio (R_B), with a conductive carbon shell, to enhance electrochemical activation and capacity compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium-rich manganese-based laminated positive electrode materials are used to achieve high specific capacity (>250 mAh/g) and high operating voltage (4.8V), then energy density is improved, but severe capacity and voltage decay occurs during long cycles resulting in poor long-cycle stability
Solution Approach 1:
The positive electrode material is divided into two distinct particle types: first particles with lower Li2O/Li2MnO3 component ratio and second particles with higher Li2O/Li2MnO3 component ratio. This segmentation allows each particle type to fulfill different functional roles - first particles provide high capacity while second particles provide structural stability and compensate for capacity decay during cycling.
Solution Approach 2:
Different regions of the electrode material have different compositional characteristics. The first particles have a specific Li2O/Li2MnO3 component ratio optimized for high capacity, while the second particles have a higher ratio optimized for stability. This local quality differentiation enables the overall material to achieve both high energy density and good long-cycle stability through synergistic effects.
2Productivity
If lithium-rich manganese-based positive electrode material is used to achieve high specific capacity, then productivity is improved, but irreversible capacity loss increases leading to severe voltage decay
Solution Approach 1:
The invention changes the compositional parameters by creating two distinct particle types with different Li2O/Li2MnO3 component ratios. The first particles have a lower ratio (optimized for capacity) while the second particles have a higher ratio (optimized for reducing irreversible loss). This parameter differentiation allows the material to maintain high specific capacity while reducing voltage decay through the stabilizing effect of the second particles.
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 synergistic effect between the first and second particles improves long-cycle stability and rate performance by reducing irreversible capacity loss and enhancing lithium ion deintercalation efficiency.
Implementation Method 1
the second particle comprises a core and a shell covering at least a portion of the surface of the core, the core satisfies chemical formula (2), and the shell comprises a conductive carbon material
Implementation Method 2
subjecting a first mixture comprising a first precursor and a first lithium source to a first sintering treatment to produce the first particle
Implementation Method 3
heating the first mixture to 300°C to 600°C at a heating rate of 1°C/min to 10°C/min, keeping at this temperature for 2 h to 8 h, then heating the first mixture to 750°C to 1000°C
Data Source
Figure 1~2
AI summary
The present application provides a lithium-rich manganese-based positive electrode material and a production method, a positive electrode sheet, a battery and an electronic device thereof. The lithium-rich manganese-based positive electrode material comprises a first particle and a second particle. The first particle satisfies chemical formula (1), and the second particle satisfies chemical formula (2): aLi2O·bLi2MnO3·cLiXαX'βO2 (1), xLi2O·yLi2MnO3·zLiYγY'δO2 (2), wherein in formula (1), -0.1≤a≤0, 0<b≤0.4, b+a>0, b+c-a=1; in formula (2), 0≤x≤0.1, 0.4<y<1, x+y+z=1; in formula (1) and formula (2), X and Y each independently include one or more of Ni and Co, X' and Y' each independently include one or more of Mn, Al, Na, Mg, B, Ti, Y, Zr, Nb, Sn, La, Ce, Ta and W, and 0≤β≤0.5≤α≤1, 0≤δ≤0.5≤γ≤1, α+β=1, γ+δ=1; the lithium-oxygen ratio of the first particle is RA=(2a+2b+c)/(a+3b+2c), and satisfies 1/2<RA<7/12; the lithium-oxygen ratio of the second particle is RB=(2x+2y+z)/(x+3y+2z), and satisfies RA<RB<5/7. The lithium-rich manganese-based positive electrode material provided in the present application has high long-cycle stability.