Thursday, January 28, 2010

Ternary Metal Transition Metal Non-Oxide Nano-Particles Make More Powerful Capacitors and Rechargeable Batteries Say Carnegie Mellon University Chemists


Carnegie Mellon University chemists have made more powerful capacitors and rechargeable batteries with ternary metal transition metal non-oxide nano-particles. 

Transition metal based non-oxide materials such as transition metal nitrides ("TMN") are known in the art for their high-melting temperature (e.g., approximately 3000.degree. C.), hardness (e.g., Hv=approximately 1800 to 2100 kg/mm2), electronic conductivity, chemical inertness, abrasion and wear resistance. These characteristics have made them useful for abrasion-resistant applications, optical coatings, low-resistivity contacts and as diffusion barrier layers in the microelectronics industry, as well as catalysts in the petroleum industry. Transition metal materials, such as TMNs, have also been found to exhibit surface-induced electrochemical characteristics rendering them useful as electrodes in capacitors.

Carnegie Mellon University Chemical Engineering Professor Prashant Nagesh Kumta, Amit Paul and Prashanth Hanumantha Jampani have manufactured ternary metal transition metal non-oxide nano-particles, methods for preparing the nano-particles and applications relating to the nano-particles in dispersions, electrodes, rechargeable batteries and capacitors.


Their U.S. Patent Application 20100019207 details ternary mixed metal transition metal non-oxide nano-particle compositions including a precursor which includes at least one material selected from the group consisting of alkoxides, carboxylates and halides of transition metals. The material consists of at least two different transition metals selected from the group consisting of vanadium, niobium, tungsten, tantalum and molybdenum.

The method of preparing a ternary mixed metal transition metal non-oxide nano-particle includes reacting at least one material selected from the group consisting of alkoxides, carboxylates and halides of transition metals, the material comprising at least two different transition metals selected from the group consisting of vanadium, niobium, tungsten, tantalum and molybdenum, with a nitrogen-containing reagent in a solvent, to form a precursor and heat treating the precursor in a nitrogen-containing atmosphere


An electrode made with the new TMNs has a capacitance of from 1300 F/g to 1400 F/g.  and a surface area of from 50 m2/g to 300 m2/g.

A capacitor made with the ternary mixed metal transition metal non-oxide nano-particle has a capacitance of at least 1340 F/g at high scan rates of 100 mV/s.

A rechargeable battery made with a ternary metal transition metal non-oxide nano-particle composition has an energy density of greater than 300 Wh/kg. The battery material includes at least one material selected from the group consisting of alkoxides, carboxylates, and halides of transition metals, the material includes at least one transition metal selected from the group consisting of vanadium, niobium, tungsten, tantalum and molybdenum.


Another aspect of the discovery relates to a dispersion which includes carbon nanotubes and ternary mixed metal transition metal non-oxide nano-particles, the nano-particles including at least one material selected from the group consisting of alkoxides, carboxylates and halides of transition metals, the material comprising at least two different transition metals selected from the group consisting of vanadium, niobium, tungsten, tantalum and molybdenum. In an embodiment, the carbon nanotubes can include single and/or multi-wall carbon nanotubes.

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