TiN-Coated Lithium Titanium Oxide Anode for High-Rate Batteries
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Solution Overview
Problem
Lithium ion secondary batteries face challenges with anode active materials, such as lithium titanium oxide (Li4Ti5O12), which have limited charging and discharging rates and ion conductivity, and carbonaceous materials that are prone to irreversible changes, necessitating a material with improved electrical conductivity and stability for high-performance batteries.
Innovation Solution
A composite anode active material is developed by incorporating a TiN layer on lithium titanium oxide particles, with a thickness of 1 nm to 20 nm, enhancing electrical conductivity and cycle stability, and prepared through a method involving mixing lithium and titanium sources with urea-based compounds and thermal treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lithium titanium oxide is used as anode active material, then high charging and discharging rate and long lifetime are achieved, but capacity per volume is reduced compared to carbonaceous materials
Solution Approach 1:
The patent creates a composite structure where lithium titanium oxide particles are coated with a carbonaceous material layer. This composite approach combines the high rate capability and long cycle life of lithium titanium oxide with the high capacity per volume of carbonaceous materials, effectively resolving the contradiction between productivity and quantity of substance.
2Quantity of substance
If carbonaceous materials are used as anode active material, then high capacity per volume is achieved, but irreversible alteration occurs during charging and discharging cycles
Solution Approach 1:
The carbonaceous material coating on lithium titanium oxide particles creates a composite structure where the inner lithium titanium oxide core provides structural stability and reversibility, while the outer carbonaceous layer provides high capacity. This composite approach resolves the contradiction between quantity of substance and reliability by combining materials with complementary properties.
3Productivity
If Li4Ti5O12 is used as anode active material, then high charging and discharging rate with nearly zero irreversible reaction is achieved, but theoretical capacity is only half that of graphite
Solution Approach 1:
The patent employs a composite structure where lithium titanium oxide provides the high rate capability and near-zero irreversible reaction characteristics, while the carbonaceous material coating contributes additional capacity. This composite approach allows the material to achieve both high productivity and increased quantity of substance by combining materials with different strengths.
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 composite anode active material exhibits improved charging and discharging rate characteristics, maintaining high capacity retention and stability, effectively addressing the limitations of existing materials by enhancing ion and electron conductivity.
Implementation Method 1
enhancing electrical conductivity and cycle stability
Implementation Method 2
Lithium ion secondary batteries generate electrical energy through oxidation and reduction reactions that take place during intercalation and deintercalation of lithium ions
Data Source
AI summary
In an aspect, a composite anode active material including lithium titanium oxide particles; and a TiN, and TiN a method of preparing the composite anode active material, and a lithium battery including the composite anode active material is provided.