Researchers have determined the now-infamous Martian rock resembling a jelly doughnut, dubbed Pinnacle Island, is a piece of a larger rock broken and moved by the wheel of NASA’s Mars Exploration Rover Opportunity in early January. Only about 1.5 inches wide (4 centimeters), the white-rimmed, red-centered rock caused a stir last month when it appeared in an image the rover took Jan. 8 at a location where it was not present four days earlier. More recent images show the original piece of rock struck by the rover’s wheel, slightly uphill from where Pinnacle Island came to rest.
The Energy Department announced that the US solar industry is more than 60 percent of the way to achieving cost-competitive utility-scale solar photovoltaic electricity – only three years into the Department’s decade-long SunShot Initiative. To help continue this progress, the Energy Department also announced today $25 million in funding to strengthen US solar manufacturing for photovoltaic and concentrating solar power technologies and to maintain a strong domestic solar industry—supporting the Department’s broader Clean Energy Manufacturing Initiative.
An electrode designed like a pomegranate with silicon nanoparticles clustered like seeds in a tough carbon rind overcomes several obstacles to using silicon for a new generation of lithium-ion batteries, say its inventors at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory. The anode stores energy when the battery charges. Silicon anodes could store 10 times more charge than the graphite anodes in today’s rechargeable lithium-ion batteries, but they also have drawbacks: The brittle silicon swells and falls apart during battery charging, and it reacts with the battery’s electrolyte to form gunk that coats the anode and degrades its performance. Over the past eight years, researchers tackled the breakage problem by using silicon nanowires or nanoparticles that are too small to break into even smaller bits and encasing the nanoparticles in carbon “yolk shells” that give them room to swell and shrink during charging.
On a pound-per-pound basis, carbon nanotube-based fibers invented at Rice University have greater capacity to carry electrical current than copper cables of the same mass, according to new research. While individual nanotubes are capable of transmitting nearly 1,000 times more current than copper, the same tubes coalesced into a fiber using other technologies fail long before reaching that capacity. But a series of tests at Rice showed the wet-spun carbon nanotube fiber still handily beat copper, carrying up to four times as much current as a copper wire of the same mass. That, said the researchers, makes nanotube-based cables an ideal platform for lightweight power transmission in systems where weight is a significant factor, like aerospace applications.
Led by Katie Zhong, professor at Washington State University, the researchers recently reported on their work in the journal, Advanced Energy Materials. They have also filed a patent. The biggest potential risk of high performance lithium batteries comes from the electrolyte in the battery, which is made of either a liquid or gel in all commercially available rechargeable lithium batteries. The liquid acid solutions can leak and even create a fire or chemical burn hazard. While commercial battery makers have ways to address these safety concerns, such as adding temperature sensors or flame retardant additives, they “can’t solve the safety problem fundamentally,’’ says Zhong. Zhong’s research group has developed a gum-like lithium battery electrolyte, which works as well as liquid electrolytes at conducting electricity but which doesn’t create a fire hazard.