Li-rich Cathode Material with TiO2 Coating for High Capacity
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Solution Overview
Problem
Lithium-rich cathode materials with a primary particle size of 500 nm or more struggle to achieve high capacity due to limited electrochemical activation, and minimizing particle size to achieve high capacity results in increased specific surface area, making practical application difficult.
Innovation Solution
A method involving the preparation of a spherical transition metal complex carbonate coated with nano-sized titanium dioxide, which is then heat-treated with lithium to create a Li-rich cathode material capable of achieving 250 mAh/g capacity or more, even with larger particle sizes, and maintaining 94% of initial capacity after 40 cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the primary particle size is reduced to 200 nm or less to achieve high capacity of 250 mAh/g or more, then the capacity increases, but the specific surface area increases making practical application difficult
Solution Approach 1:
The cathode material is structured as spherical particles with a core-shell configuration, where the core contains the Li-rich layered structure and the shell contains titanium dioxide coating. This segmentation allows the internal core to provide high capacity while the external shell controls surface interactions, enabling practical application with reduced specific surface area effects.
Solution Approach 2:
The invention uses a composite structure combining Li-rich layered cathode material with titanium dioxide coating. The composite material integrates the high capacity characteristics of Li-rich materials with the surface stability and protective properties of titanium dioxide, resolving the contradiction between high capacity and practical applicability.
2Quantity of substance
If the primary particle size is reduced to enhance electrochemical activation, then the capacity increases, but the manufacturing and handling become difficult
Solution Approach 1:
The cathode material is designed with a spherical particle morphology. This spheroidality improves flowability, packing density, and handling characteristics compared to irregularly shaped particles of the same size, while maintaining the small particle size needed for high capacity and electrochemical activation.
3Quantity of substance
If titanium is substituted into Li2MnO3 to facilitate electrochemical activation, then the capacity increases, but the structural stability may be affected
Solution Approach 1:
Titanium substitution is implemented locally within the Li2MnO3 lattice structure rather than uniformly throughout. This localized substitution facilitates electrochemical activation in specific regions while maintaining overall structural stability, as the titanium atoms are incorporated at controlled concentrations and positions within the crystal lattice.
Solution Approach 2:
The invention creates a composite structure where titanium dioxide is coated on the surface of Li-rich particles, and titanium is also substituted into the bulk lattice. This multi-level composite approach provides both electrochemical activation benefits and structural stability, as the titanium dioxide shell protects the core while the substituted titanium enhances activation.
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 solution enables a Li-rich cathode material with enhanced electrochemical performance, achieving high capacity and extended life expectancy by uniformly diffusing titanium into the material, inhibiting structural changes during charging and discharging, and maintaining capacity and hardness.
Implementation Method 1
a process of coating a surface of the spherical transition metal complex carbonate with nano-sized titanium dioxide
Implementation Method 2
a process of mixing a lithium (Li) material with the transition metal complex carbonate coated with titanium dioxide and heat-treating the mixture to prepare a spherical Li-rich cathode material
Implementation Method 3
by uniformly diffusing titanium into the material, inhibiting structural changes during charging and discharging
Implementation Method 4
a process of preparing a spherical transition metal complex carbonate substituted with other metals by co-precipitating an aqueous solution in which a nickel material, a cobalt material, a manganese material, a carboxyl group material, and an ammonia material are mixed
Data Source
AI summary
The present invention relates to a non-aqueous cathode material for lithium secondary batteries using a spherical transition metal complex carbonate, and a method for preparing same. According to the present invention, since the surface of a spherical transition metal complex carbonate, which is prepared by using a cobalt material, nickel material, manganese material, carboxyl group material, and ammonia material, is coated with titanium dioxide. In addition, by mixing the prepared, surface-coated transition metal complex carbonate with a lithium material and heat-treating the resultant material, it is possible to prepare a spherical Li-rich cathode material having a primary particle size of 200 nm or more, and a 0.1 C capacity of 250 mAh/g or more, and capable of implementing 96% or more of the initial capacity in a full cell after charging and discharging 60 times.