Abstract:
Identifying marks are often used for authentication and tracking purposes with various types of articles, but they can sometimes be subject to replication or removal by an outside entity, such as a person or group having malicious intent. Carbon nanotubes and other carbon nanomaterials can be used to form identifying marks that are not visible to the naked eye, thereby making the marks more difficult for an outside entity to tamper with. Various articles can include an identifying mark that is not visible to the naked eye, the identifying mark containing a nanomaterial that includes a plurality of carbon nanotubes with a registered distribution of chiralities. The registered distribution of chiralities can be further tailored to increase the level of security provided by the mark.
Abstract:
Conventional rechargeable batteries, such as lithium-ion batteries, are somewhat limited in their energy storage density. Sulfur-based batteries can provide improved energy storage density, but their use can be hampered by sulfur's low electrical conductivity. Energy storage devices, particularly batteries, can have a first electrode that includes a carbon nanotube aerogel, and an electroactive material containing sulfur that is incorporated in the carbon nanotube aerogel. Methods for forming an energy storage device can include incorporating an electroactive material containing sulfur in a carbon nanotube aerogel, compressing the carbon nanotube aerogel to form a compressed carbon nanotube aerogel, and disposing a first electrode containing the compressed carbon nanotube aerogel and the electroactive material in an electrolyte with a second electrode and a plurality of lithium ions, such that a separator material permeable to the lithium ions is between the first electrode and the second electrode.