LTO Carbon Composite Electrode Conductivity
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Solution Overview
Problem
Conventional lithium titanium oxide (LTO) materials used in hybrid super capacitors and lithium secondary batteries suffer from low electronic conductivity and limited theoretical capacity, leading to reduced performance and productivity due to increased resistance with thickness and low cycle efficiency.
Innovation Solution
A lithium titanium oxide (LTO)/carbon composite is formed by introducing a carbon-based additive into the voids of LTO granules, enhancing electrical conductivity and specific surface area through a heat treatment process, which includes preparing a mixed material with lithium and titanium precursors and a carbon-based additive, followed by oven or spray drying and heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LTO is used as negative electrode material, then structural stability is achieved, but electrical conductivity is low leading to increased resistance
Solution Approach 1:
The patent creates a composite material by filling voids in LTO granules with carbon-based additives. This composite structure combines the structural stability of LTO with the high electrical conductivity of carbon, resolving the contradiction between reliability and energy loss. The carbon material forms a conductive network within the LTO matrix, enabling efficient electron transport while maintaining the spinel structure's stability.
Solution Approach 2:
The patent utilizes the porous void structure of LTO granules and fills it with conductive carbon material. This approach transforms the previously harmful porosity (which caused low conductivity) into a beneficial feature by using the void space to host a conductive phase, thereby improving electrical conductivity without compromising structural stability.
2Quantity of substance
If electrode thickness is increased to improve capacity, then electrostatic capacity increases, but resistance increases leading to reduced output
Solution Approach 1:
The carbon-LTO composite creates a conductive network that penetrates throughout the electrode thickness. This conductive pathway allows electrons to travel efficiently from deep within thick electrodes to the current collector, enabling the use of thicker electrodes for higher capacity without suffering from increased resistance.
Solution Approach 2:
The carbon-based additive is selectively placed in the voids of LTO granules, creating local conductive regions throughout the electrode. This local quality enhancement ensures that every region of the thick electrode has adequate conductivity, preventing resistance buildup even as overall electrode thickness increases.
3Ease of manufacture
If conventional LTO preparation method is used, then manufacturing process is simple, but productivity is reduced due to need for thin film formation
Solution Approach 1:
The patent combines multiple functions into a single preparation process: the carbon-based additive is mixed with LTO precursors before firing, so that the conductive network is formed simultaneously with the LTO granule structure. This merging of structure formation and conductive network creation eliminates the need for separate thin-film coating steps, improving productivity while maintaining ease of manufacture.
Solution Approach 2:
The carbon-based additive is incorporated into the LTO precursor mixture before the firing process. This preliminary action ensures that the conductive network is formed in advance during the standard LTO synthesis, eliminating the need for subsequent thin-film formation steps and thereby improving production efficiency without complicating the manufacturing process.
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 LTO/carbon composite improves electrical conductivity, increases electrostatic capacity, and simplifies the production process, resulting in enhanced output characteristics and productivity for negative electrode materials in hybrid super capacitors and lithium secondary batteries.
Implementation Method 1
performing a heat treatment on the dried mixture at 700 to 900° C. under the nitrogen (N2) or argon (Ar) atmosphere to form LTO granules having a plurality of voids and introduce a carbon-based additive into a plurality of the voids
Data Source
AI summary
A lithium titanium oxide (LTO)/carbon composite, a preparation method for the LTO/carbon composite, a negative electrode material using the LTO/carbon composite, and a hybrid super capacitor using the negative electrode material are disclosed. The lithium titanium oxide (LTO)/carbon composite is formed to insert a carbon-based additive into a plurality of voids formed on the LTO granules, thereby improving the electrical conductivity.