Titanium-Niobium Composite Oxide Electrode with Carbon Interlayer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion secondary batteries using carbon-based materials face issues with rapid charge and discharge due to dendrite formation, leading to internal short circuits and reduced energy density when using titanium-based materials, which have lower capacity and conductivity.
Innovation Solution
A composite structure incorporating a titanium-niobium composite oxide with a graphene sheet and a carbon layer between the graphene and the active material particles, enhancing conductivity and stability through π-π interactions and Van der Waals forces, preventing separation and improving bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If carbon-based materials are used in the negative electrode, then capacity is improved, but dendrite precipitation occurs during rapid charge and discharge
Solution Approach 1:
A lithium phosphate coating layer is applied to the surface of the carbon-based negative electrode material. This intermediate layer prevents direct contact between lithium ions and the carbon surface during rapid charging, blocking dendrite formation while still allowing lithium ion insertion and extraction, thus maintaining capacity while improving safety and reliability
Solution Approach 2:
The negative electrode is designed as a composite structure combining carbon-based materials (for high capacity) with a lithium phosphate coating layer (for dendrite prevention). This composite approach allows the electrode to simultaneously achieve high capacity retention and resistance to dendrite precipitation during rapid charge and discharge cycles
2Reliability
If titanium-based materials are used to avoid dendrites, then safety is improved, but energy density decreases due to lower capacity
Solution Approach 1:
A lithium phosphate coating layer is applied to the titanium-based negative electrode material. This intermediate layer enhances lithium ion conductivity at the surface, allowing the titanium-based material to achieve higher capacity and energy density while maintaining its inherent safety advantages and resistance to dendrite formation
Solution Approach 2:
The negative electrode is designed as a composite combining titanium-based materials (for safety and dendrite resistance) with a lithium phosphate coating layer (for enhanced conductivity and capacity). This composite structure enables the electrode to achieve both high safety/reliability and high energy density by leveraging the strengths of both materials
3Reliability
If titanium-based materials are used, then dendrite formation is prevented, but conductivity is reduced
Solution Approach 1:
A lithium phosphate coating layer is applied to the titanium-based negative electrode material. This intermediate layer has superior lithium ion conductivity compared to the bulk titanium-based material, creating a high-conductivity surface pathway for lithium ion transport while the bulk material maintains its dendrite-preventing properties
Solution Approach 2:
The electrode structure is designed with spatially varying properties: the surface layer (lithium phosphate coating) provides high conductivity for rapid lithium ion transport, while the bulk material (titanium-based) provides dendrite prevention. This local differentiation of functions allows the electrode to simultaneously achieve high conductivity and reliable dendrite prevention
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 composite structure enables a nonaqueous electrolyte battery with excellent capacity retention and stability during repetitive charge and discharge cycles, overcoming the limitations of titanium-based materials in energy density and conductivity.
Implementation Method 1
enhancing conductivity and stability through π-π interactions and Van der Waals forces
Implementation Method 2
enhancing conductivity and stability through π-π interactions and Van der Waals forces
Implementation Method 3
The carbon layer includes a carbon material having a π-electron system
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
According to one embodiment, there is provided a composite (10) active material comprising active material particles (11) which include a titanium-niobium composite oxide. The composite (10) further includes a graphene sheet material (13) and a carbon layer (12), said carbon layer being located between the graphene sheet material (13) and the active material particles (11). The graphene sheet material (13) includes at least one of a planar graphene sheet of a monoatomic layer and a laminate of 10 layers or less of the planar graphene sheets. The active material particles (11) include a titanium-niobium composite oxide. The carbon layer includes a carbon material having a π-electron system. Thanks to the π-π interaction between the graphene sheet and the carbon material, the bonding between the active material particles and the graphene sheet is strengthened and excellent stability against repetitive charge and discharge can be exhibited.