NCM Cathode Coating and Si-Additive Electrolyte for High-Voltage Cycling
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Solution Overview
Problem
Existing secondary batteries face challenges in achieving high energy density and good cycling performance, particularly when operating at high voltages, due to issues like cation mixing, irreversible phase transitions, and increased impedance in nickel-cobalt-manganese ternary materials.
Innovation Solution
A battery cell design featuring a positive electrode active material with a doped nickel-cobalt-manganese inner core coated with a specific element Y, combined with an electrolyte solution containing a first additive with Si—N and Si—O bonds, forms a low-impedance interface film that inhibits LiPF6 decomposition and enhances ion conductivity, improving structural stability and cycling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If nickel-cobalt-manganese ternary material is used as positive electrode active material, then energy density is improved, but structural stability deteriorates during charge-discharge cycling at high voltage
Solution Approach 1:
The patent uses a composite material structure where element Y is doped into the nickel-cobalt-manganese ternary material lattice. This creates a composite structure that combines the high energy density characteristics of the original ternary material with the structural stability provided by the doped element Y, resolving the contradiction between energy density and structural stability.
Solution Approach 2:
The patent changes the compositional parameters of the positive electrode active material by controlling the doping content of element Y within specific ranges (0.01≤b≤0.15, 0.1≤c≤0.5). By optimizing these parameters, the material achieves both high energy density and improved structural stability during cycling.
2Use of energy by moving object
If high voltage operation is implemented, then energy density is improved, but impedance increases
Solution Approach 1:
The patent changes the electrochemical parameters by introducing element Y doping and controlling the lithium content (0.2≤x≤1.3). These parameter changes enable the material to operate at high voltage while maintaining low impedance through optimized electronic and ionic conductivity.
3Use of energy by moving object
If high voltage charge-discharge cycling is performed, then energy density is improved, but cycling performance deteriorates
Solution Approach 1:
The doped nickel-cobalt-manganese ternary material creates a composite structure where element Y reinforces the crystal lattice, preventing irreversible phase transitions during high voltage cycling. This composite structure maintains both high energy density and reliable cycling performance.
Solution Approach 2:
The element Y doping acts as a preliminary protective measure that prevents structural degradation before it occurs. By pre-stabilizing the crystal structure through doping, the material resists cation mixing and phase transitions during subsequent high voltage cycling, maintaining cycling performance.
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 battery cell achieves both high energy density and good cycling performance by reducing impedance, inhibiting HF generation, and maintaining stable lithium ion transmission, thereby extending the battery's life and capacity.
Implementation Method 1
The Si—N bond of the first additive is easily bonded to a nucleophilic substance in the electrolyte solution to form a silicon-based derivative
Implementation Method 2
thereby forming a low-impedance interface film on the surface of the positive electrode plate and the negative electrode plate
Implementation Method 3
The inner core comprises Lix (NiaCobMnc)dMeOfAy, where M includes one or more of Zr, Sr, B, Ti, Mg, Sn, Tb, W, Nb, Sb, or Al
Implementation Method 4
a coating layer coating the inner core. The coating layer comprises element Y
Implementation Method 5
maintaining stable lithium ion transmission
Data Source
AI summary
A battery cell, a battery including the battery cell, and an electrical apparatus are provided. The battery cell includes a positive electrode plate and an electrolyte solution. The positive electrode plate contains a positive electrode active material comprising an inner core and a coating layer. The inner core includes a lithium-containing complex with nickel, cobalt, manganese, and additional elements selected from one or more of zirconium, strontium, boron, titanium, magnesium, tin, terbium, tungsten, niobium, antimony, or aluminum, as well as anions selected from sulfur, nitrogen, fluorine, chlorine, bromine, or iodine. The coating layer includes one or more metal elements selected from cobalt, zirconium, strontium, boron, titanium, magnesium, tin, terbium, tungsten, niobium, antimony, or aluminum. The electrolyte solution includes an additive containing an organic compound with both silicon-nitrogen and silicon-oxygen bonds. This combination improves the electrochemical performance and stability of the battery during operation.