Lithium Iron Titanium Oxide Anode for High-Rate Li-Ion Charging
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Solution Overview
Problem
Lithium titanium oxide negative electrode materials for lithium-ion batteries suffer from low specific capacity, poor conductivity, and poor high-rate charging and discharging performance due to their insulating nature and low electronic and ionic conductivity, along with challenges in particle growth control and tap density during high-temperature synthesis.
Innovation Solution
A modified lithium iron titanium oxide material is synthesized using a citric acid sol-gel method, which involves adding an organic acid to an iron salt solution, dissolving titanium and lithium sources in alcohol, adjusting pH, and performing heat treatment under reducing conditions to achieve a LiFeTiOx composite oxide with improved conductivity and specific capacity through controlled doping and nano-scale particle formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If doping modification is performed on spinel-type lithium titanium oxide to improve conductivity and charging-discharging performance, then the electrical conductivity and large-current charging-discharging capability are improved, but the preparation process becomes more complex and requires additional doping steps
Solution Approach 1:
The patent combines multiple functions into a single preparation process: the sol-gel method simultaneously achieves uniform doping of Fe elements, controlled nano-scale particle formation, and organic acid residue carbonization. This merging of doping, particle size control, and surface modification into one integrated process resolves the contradiction by improving conductivity without proportionally increasing process complexity
Solution Approach 2:
The patent uses parameter changes in the sol-gel process (pH adjustment to 5.0-7.0, controlled calcination temperature, reducing atmosphere heat treatment) to optimize the doping effect and particle morphology. By carefully controlling these parameters, the preparation process achieves improved conductivity and performance while maintaining reasonable process complexity
2Stability of the object's composition
If high-temperature calcination is used to synthesize lithium titanium oxide, then the material crystallinity is improved, but high-temperature runaway may occur and the preparation process becomes more hazardous
Solution Approach 1:
The sol-gel process performs preliminary formation of a homogeneous precursor gel with uniformly distributed metal ions before calcination. This preliminary action ensures that the subsequent calcination proceeds more uniformly and at lower temperatures, reducing the risk of high-temperature runaway while still achieving good crystallinity
Solution Approach 2:
The organic acid (citric acid) acts as an intermediary that controls the decomposition and carbonization process during calcination. It serves as a fuel source that promotes uniform heating and prevents localized overheating, thereby reducing runaway risk while maintaining crystallinity. The carbon residues from organic acid also serve as conductive additives
3Reliability
If the particle size of lithium titanium oxide is reduced to nano-scale, then the specific capacity and conductivity are improved, but the control of particle growth becomes more difficult during synthesis
Solution Approach 1:
The sol-gel method creates local homogeneous environments where metal ions are uniformly distributed in the gel matrix. This local uniformity ensures consistent nucleation and growth conditions throughout the material, enabling precise control of particle size and morphology while achieving nano-scale dimensions with improved specific capacity
Solution Approach 2:
The patent controls particle growth by adjusting key sol-gel parameters: pH value (5.0-7.0) controls gelation and particle formation, calcination temperature controls crystallization, and reducing atmosphere controls surface modification. These parameter changes enable precise particle growth control while achieving the desired nano-scale morphology
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 modified material significantly enhances charging and discharging capacity, improves large-current charging and discharging performance, and maintains stability, addressing the limitations of lithium titanium oxide by increasing electronic conductivity and specific capacity.
Implementation Method 1
the organic acid is a complexing agent
Implementation Method 2
drying and crushing the wet gel, and then calcinating to obtain a LiFeTiO4 composite oxide
Implementation Method 3
calcinating to obtain a LiFeTiO4 composite oxide
Implementation Method 4
under the action of a reducing gas, performing a heat treatment on the LiFeTiO4 composite oxide to obtain the modified lithium ion negative electrode material, wherein the chemical formula of the modified lithium ion negative electrode material is LiFeTiOx, where 1<x<2
Implementation Method 5
A spinel modified negative electrode material lithium iron titanium oxide is synthesized by using a citric acid sol-gel method
Implementation Method 6
dropwise adding the solution II into the solution I, adjusting the pH to 5.0-7.0, and continuing stirring to obtain a wet gel
Implementation Method 7
since the organic acid is used as a complexing agent, residual conductive carbon will be formed on the oxide surface during calcination
Data Source
Figure 1~2
Figure 3~4
AI summary
The present disclosure relates to the technical field of batteries, and in particular, to a modified lithium ion negative electrode material, and preparation therefor and use thereof. The preparation method includes the following steps: dropwise adding a mixed solution of a titanium source and a lithium source into a mixed solution of an iron salt and an organic acid, adjusting the pH to 5.0-7.0, and stirring to obtain a wet gel; drying and crushing the wet gel, and then calcinating to obtain a LiFeTiO4 composite oxide; and reducing the LiFeTiO4 composite oxide to obtain the modified lithium ion negative electrode material. In the present disclosure, a spinel modified negative electrode material lithium iron titanium oxide is synthesized by using a citric acid sol-gel method, thereby not only greatly improving the charging and discharging capacity thereof, but also improving the large-current charging and discharging capability thereof.