Lithium-Insertion Composite Oxide Coating for Battery Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nonaqueous electrolyte batteries face challenges with rapid charge and discharge, leading to dendrite formation and internal short-circuits, and have low energy density due to the use of titanium oxides as negative electrode active materials, which also result in degraded cycle characteristics due to decomposition reactions with fluorine-containing electrolytes.
Innovation Solution
Development of an active material with lithium insertion and extraction potentials between 0.5 V to 2 V, coated with carbon material layers having a specific surface area and mass ratio, inhibiting decomposition reactions and enhancing electron conductivity while preventing lithium deposition on electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If titanium oxides are used as negative electrode active materials to achieve stable rapid charge and discharge, then reliability is improved, but energy density deteriorates
Solution Approach 1:
The patent changes the electrode potential parameter by using a metal composite oxide with a potential of 0.5V to 2.0V vs Li+/Li, which is lower than conventional titanium oxides (1.5V). This parameter change enables higher energy density while maintaining rapid charge-discharge stability through the specific redox reactions of the metal composite oxide.
Solution Approach 2:
The patent uses a metal composite oxide containing multiple metal elements (e.g., Mn, Ni, Co, Fe combined with Ti) instead of single-element titanium oxide. This composite material approach provides both the desired electrode potential range and high capacity, resolving the contradiction between reliability and energy density.
2Quantity of substance
If carbonaceous materials are used as negative electrode active materials to increase capacity, then energy density is improved, but reliability deteriorates due to dendrite formation
Solution Approach 1:
The patent changes the electrode potential parameter to 0.5V-2.0V vs Li+/Li, which is higher than carbonaceous materials. This potential range prevents lithium dendrite formation while maintaining high capacity through the metal composite oxide's inherent properties, thus improving reliability without sacrificing energy density.
3Quantity of substance
If electrode potential is lowered to improve energy density, then capacity is improved, but reliability deteriorates due to decomposition reactions with fluorine-containing electrolytes
Solution Approach 1:
The patent optimizes the electrode potential parameter to a specific range (0.5V-2.0V vs Li+/Li) that balances energy density and reliability. Within this range, the metal composite oxide achieves high capacity while the specific material composition prevents decomposition reactions with fluorine-containing electrolytes, maintaining good cycle characteristics.
Solution Approach 2:
The patent uses a composite oxide structure where multiple metal elements work synergistically. This composite material provides both the necessary low potential for high energy density and the chemical stability to resist decomposition reactions with fluorine-containing electrolytes, resolving the contradiction between capacity and cycle life.
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 active material improves cycle characteristics and prevents internal short-circuits by maintaining high electron conductivity and inhibiting side reactions, leading to enhanced performance in nonaqueous electrolyte batteries.
Implementation Method 1
The potential of the titanium oxide is derived from a redox reaction between Ti3+ and Ti4+ in the electrochemical insertion and extraction of lithium
Implementation Method 2
decomposition reactions of the nonaqueous electrolytic solutions proceed with extraction of lithium ions included in the active materials, thereby generating inorganic films such as LiF and Li2CO3
Data Source
AI summary
According to one embodiment, an active material is provided. This active material includes active material particles each allowing lithium to be inserted thereinto and extracted therefrom in the range of 0.5 V to 2V (vs. Li+/Li), and carbon material layers at least partially coating the active material particles. The active material has a BET specific surface area S of 2 m2/g to 20 m2/g in accordance with a nitrogen adsorption method. Between the BET specific surface area S and the proportion M (mass %) of the mass of the carbon material layers to the total mass of the active material particles and carbon material layers, the ratio of S/M (m2/g) meets 0.5≤S/M≤5.