Titanium-Niobium Mixed Oxide Synthesis for High-Rate Lithium Electrodes
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Solution Overview
Problem
Existing lithium accumulators face challenges in achieving high energy density and reversibility, particularly at high speeds, due to limitations in electrode materials like mixed titanium and niobium oxides which require restrictive experimental conditions for synthesis and suffer from capacity loss.
Innovation Solution
A solvothermal synthesis process for mixed titanium and niobium oxides that does not require vacuum or inert atmospheres, involving solvothermal treatment, mechanical grinding, and calcination, optimizing the material's ionic conductivity and electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If niobium doping and carbon coating are performed to improve high-speed capacity retention, then capacity retention is improved, but the process requires vacuum and inert atmosphere conditions that are difficult to achieve on an industrial scale
Solution Approach 1:
The patent changes the synthesis parameters by using solvothermal treatment instead of vacuum/inert atmosphere methods. The solvothermal process uses aqueous or organic solvent systems at elevated temperatures and pressures to achieve niobium doping and carbon coating without requiring vacuum or inert atmosphere conditions, thus improving ease of manufacture while maintaining capacity retention
Solution Approach 2:
The patent replaces the mechanical vacuum and inert atmosphere systems with a chemical solvothermal system. Instead of using physical vacuum pumping and inert gas flow systems, the invention uses controlled chemical reactions in a solvent environment under autoclave conditions to achieve the same doping and coating effects
2Quantity of substance
If sol-gel synthesis of TiNb2O7 is used to improve low-speed capacity, then low-speed capacity reaches 280 mAh/g, but capacity decreases during high-speed operation
Solution Approach 1:
The patent creates a composite structure by simultaneously achieving niobium doping and carbon coating in the solvothermal process. The carbon-coated niobium-doped titanium oxide composite material combines the high capacity of niobium-doped TiNb2O7 with the high conductivity and high-speed performance of carbon, resolving the contradiction between low-speed capacity and high-speed performance
3Device complexity
If solid-state synthesis method is used to prepare mixed titanium and niobium oxide, then the process is simpler, but the material requires vacuum and inert atmosphere for doping and coating steps
Solution Approach 1:
The patent merges multiple separate steps (niobium doping, carbon coating, and material synthesis) into a single solvothermal treatment step. By using precursor salts that contain both niobium and carbon sources, the process achieves all modifications simultaneously in one autoclave treatment, eliminating the need for separate vacuum and inert atmosphere steps
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 process enhances the specific capacity and high-speed performance of the mixed oxide, allowing for improved energy storage capabilities in lithium accumulators without the need for specialized experimental conditions.
Implementation Method 1
preparation of a mixed titanium and niobium oxide in amorphous form by solvothermal treatment of at least one titanium precursor and at least one niobium precursor
Implementation Method 2
calcination of the mixed oxide obtained after mechanical grinding
Data Source
Figure 1a)~2b)
Figure 3a)~4b)
Figure 5a)~6b)
AI summary
This method for preparing a titanium and niobium mixed oxide comprises the following steps: -preparation of a titanium and niobium mixed oxide in amorphous form by solvothermal treatment of at least one titanium precursor and at least one niobium precursor; -mechanical crushing of the titanium and niobium mixed oxide obtained from the solvothermal treatment; -calcination of the mixed oxide obtained after crushing.