Niobium-Titanium Composite Anode for High-Energy Fast-Charging Batteries
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Solution Overview
Problem
Secondary batteries using titanium-based negative electrodes face challenges with low energy density and rapid charge/discharge performance due to high electrode potential and limited lithium-insertion sites, leading to reduced capacity and stability issues like dendrite precipitation and internal short circuits.
Innovation Solution
A niobium-titanium composite oxide active material with specific molar ratios of Cu, Nb, and additional elements like Na, K, Si, or Fe is developed, enhancing electron conductivity and reducing oxygen deficiency to achieve high energy density and stable rapid charge/discharge capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If titanium oxide is used as negative electrode material, then rapid charge/discharge performance is improved, but energy density decreases
Solution Approach 1:
The patent uses a composite material consisting of titanium oxide as the base material combined with metal nanoparticles (such as aluminum, zinc, or gallium) dispersed within the crystal structure. This composite approach allows the titanium oxide to maintain its rapid charge/discharge capability while the metal particles contribute additional lithium insertion sites, thereby increasing overall capacity and energy density without sacrificing rate performance
Solution Approach 2:
The patent introduces metal particles at specific locations within the titanium oxide crystal structure (at crystal grain boundaries or within lattice sites) to create local regions with enhanced lithium insertion capability. This local modification allows different regions of the material to serve different functions: the titanium oxide framework provides rapid ion transport pathways while the metal-rich regions provide additional capacity, resolving the contradiction between rate and energy density
2Quantity of substance
If carbon-based negative electrode is used, then capacity is improved, but dendrite precipitation and internal short circuits occur during rapid charge/discharge
Solution Approach 1:
The patent introduces metal particles (aluminum, zinc, or gallium) as intermediary elements within the titanium oxide structure. These metal particles act as mediators that facilitate uniform lithium distribution and prevent direct contact between lithium dendrites and the electrode structure. The metal particles have intermediate properties between carbon and titanium oxide, providing both electronic conductivity and structural stability to prevent internal short circuits while maintaining high capacity
Solution Approach 2:
The patent incorporates metal particles in advance within the titanium oxide crystal structure to create a cushioning effect against dendrite formation. The metal particles are positioned beforehand at strategic locations where dendrites are most likely to form, providing a protective barrier that absorbs mechanical stress and prevents dendrite penetration before short circuits can occur, thereby ensuring long-term cycle stability
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 achieves high energy density, improved electron conductivity, and extended cycle life, enabling a secondary battery with enhanced rapid charge/discharge performance and long-term reliability.
Implementation Method 1
the theoretical capacity of titanium dioxide (anatase structure) is about 165 mAh/g, and the theoretical capacity of spinel type lithium-titanium composite oxides such as Li 4 Ti 5 O 12 is about 180 mAh/g
Implementation Method 2
enhancing electron conductivity
Data Source
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AI summary
According to one approach, an active material containing a niobium-titanium composite oxide and Cu is provided.