Titanium Niobate Core-Shell Particles for Conductive Fast-Charge Anodes
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Solution Overview
Problem
Conventional carbon negative electrodes in lithium-ion batteries face issues with cycle lifetime, safety, fast charging, and energy density, while titanium niobate, despite having higher capacity and energy density, suffers from poor electrical conductivity, limiting its application in power lithium batteries.
Innovation Solution
A core-shell particle structure is developed, where a titanium niobate core is coated with a shell layer containing copper, niobium, titanium, and oxygen, enhancing electrical conductivity and improving charge-discharge capacity and cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If titanium niobate is used as negative electrode material, then capacity and energy density are improved, but electrical conductivity deteriorates
Solution Approach 1:
The patent applies composite materials by creating a core-shell structure where the core is made of titanium niobate (TiNb2O7) particles and the shell is made of carbon material. This composite structure combines the high capacity and energy density of titanium niobate with the excellent electrical conductivity of carbon, thereby resolving the contradiction between capacity improvement and conductivity deterioration.
Solution Approach 2:
The patent uses a carbon shell layer wrapping around the titanium niobate core particles. This thin film shell provides a conductive pathway for electrons while maintaining the high capacity characteristics of the inner titanium niobate core, effectively solving the electrical conductivity issue without sacrificing capacity.
2Reliability
If conventional carbon negative electrode is used, then electrical conductivity is good, but cycle lifetime and safety deteriorate
Solution Approach 1:
The core-shell composite structure combines carbon shell (providing conductivity) with titanium niobate core (providing long cycle life and safety). This composite approach allows the battery to achieve both good electrical conductivity and extended cycle lifetime, resolving the contradiction between conductivity and durability.
Solution Approach 2:
The patent applies local quality by assigning different functions to different parts of the particle: the carbon shell provides electrical conductivity and structural stability, while the titanium niobate core provides high capacity and long cycle life. This functional differentiation resolves the contradiction by optimizing each region for its specific purpose.
3Productivity
If fast rechargeable negative electrode material is used, then charging rate is improved, but energy density deteriorates
Solution Approach 1:
The core-shell composite structure enables the material to exhibit both fast charging capability (inherited from titanium niobate's inherent properties) and high energy density (enhanced by the optimized core-shell configuration). The carbon shell ensures rapid electron transport while the titanium niobate core provides high capacity, resolving the contradiction between charging rate and energy density.
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 core-shell particle design improves the charge-discharge capacity and cycle life of lithium-ion batteries, making titanium niobate suitable for fast rechargeable applications by addressing conductivity and durability challenges.
Implementation Method 1
a shell layer, wrapping at least a portion of the surface of the core, and the shell layer includes Cu, Nb, Ti, and O
Implementation Method 2
titanium niobate (TiNb2O7, TNO) is suitable for use as a fast rechargeable negative electrode of the next generation due to higher theoretical capacity ( ̃380 mAh/g), having working potential of 1.6V
Data Source
AI summary
A core-shell particle includes a core having a chemical structure of Ti(1-x)M1xNb(2-y)M2yO(7-z)Qz, in which M1 is Li or Mg; M2 is Fe, Mn, V, Ni, Cr, or Cu; Q is F, Cl, Br, I, or S; x is 0 to 0.15; y is 0 to 0.15; and z is 0 to 2; and a shell layer wrapping at least a portion of the surface of the core, and the shell layer includes Cu, Nb, Ti, and O.