The present invention introduces an air-stable sodium titanate-based anode material for Na-ion batteries, composed of 70-72 vol.% Na2Ti3O7 and 28-30 vol.% Na2Ti6O13, referred to as 8Bi-phase NTO.9 This material can be used to prepare high- performance, 'aqueous processed' anodes for Na-ion batteries. The synthesized 8Bi-phase NTO9 remains stable even after 40 days of air exposure, simplifying storage and handling. Additionally, the composite of 8Bi-phase NTO9 and 20% functionalized multi-walled carbon nanotubes (FCNT) by mass (i.e., 8Bi-phase NTO9/FCNT) demonstrates superior cyclic stability and rate-capability as an anode material for Na-ion batteries. This holds true even for aqueous-processed electrodes, which use a water-soluble binder (Na-alginate), compared to non-aqueous processed electrodes that use the conventional Polyvinylidene fluoride (PVDF) binder and toxic, hazardous, and expensive N-Methyl-2-Pyrrolidone (NMP) solvent. Consequently, this invention highlights the development and application of an environmentally and health-friendly, high-performance, and safe anode for Na-ion batteries.
Figure (1) SEM of the prepared Bi-phase NTO.
The air and moisture stability of a material significantly influences the storage and processing conditions, thereby impacting the cost of Na-ion batteries. In the case of Na2Ti3O7, Na+ ions can exchange with H+ ions, leading to the formation of H2Ti3O7 when exposed to moisture. In contrast, Na2Ti6O13 is highly stable when exposed to air. Furthermore, the commonly used binder PVDF, which utilizes toxic NMP as a solvent, poses health and environmental hazards, is costly, and forms an unstable solid electrolyte interphase (SEI) with Na-titanate-based materials.
- Improved Cyclic Stability and Rate-Capability: Demonstrates excellent cyclic stability and rate-capability compared to conventional PVDF-NMP based counterparts.
- Eco-Friendly Battery Design: Develops environmentally and health-friendly Na-ion batteries using Bi-phase Na-titanate (NTO) combined with functionalized carbon nanotubes (FCNT)
- Enhanced Air Stability: Enhances the air-stability of Bi-phase NTO through the presence of Na¢Ti¦O¡£ on its outer surface, offering improved material longevity.
- Green Slurry Formulation: Utilizes a water-soluble binder, sodium alginate, along with water as the slurry medium, replacing toxic solvents for safer and greener processing.
- Uniform CNT Wrapping: Achieves uniform wrapping of functionalized multi-walled carbon nanotubes (MWCNTs) around Na-titanates, contributing to enhanced cyclic performance and improved rate-capability.
The present invention discloses the synthesis, development, and electrochemical performance of an air-stable bi-phase sodium titanate-based anode material for Na-ion batteries. The material comprises Na¢Ti£O§ as the primary phase (70–72 vol.%) and Na¢Ti¦O¡£ as the secondary phase (28–30 vol.%). The synthesis involves dissolving titanium (IV) butoxide in butanol in a 1:1 volume ratio at 60°C, and separately dissolving sodium hydroxide (Merck) in distilled water at a 1:25 mass ratio at the same temperature. The sodium hydroxide solution is then added to the titanium (IV) butoxide solution along with excess distilled water under constant stirring. The resulting mixture is further stirred at 80°C, dried at 110°C for 12 hours, and then calcined at 800°C for 10 hours in an argon atmosphere to yield the bi-phase NTO. This material demonstrates excellent electrochemical performance, retaining 97% of its capacity (measured at C/5) after 25 charge-discharge cycles.
The invention is at the stage of having components validated in laboratory environment.
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The invention addresses key environmental, health, and economic challenges associated with the development of Na-ion batteries. The use of water-soluble binder and non-toxic, inexpensive materials significantly diminishes the environmental and health hazards posed by traditional methods.
- Energy Storage Systems: Enhances the performance and safety of Na-ion battery technologies.
- Consumer Electronics: Suitable for smartphones, laptops, tablets, and other portable devices.
- Automotive Industry: Applicable in electric vehicles and hybrid systems requiring stable energy storage.
- Renewable Energy Systems: Supports grid-level and off-grid storage for solar and wind energy.
- Industrial Equipment: Provides durable and safe power sources for heavy-duty operations.
- Aerospace Sector: Useful for high-reliability power solutions in aerospace applications.
- Medical Devices: Ensures safe and long-lasting energy for portable and implantable devices.
- Green Technologies: Aligns with sustainable initiatives due to its eco-friendly materials and processing.
Geography of IP
Type of IP
202321004250
454555