A research team headed by Hongjie Dai of Stanford University recently announced "[a]n ultrafast nickel–iron battery from strongly coupled
inorganic nanoparticle/nanocarbon hybrid materials" in the journal Nature Communications. The researchers developed inorganic nanoparticles coupled with carbon nanotubes and graphene to use as the electrodes. They claimed to increase charging and discharging rates by a factor of almost 1,000 over traditional Ni-Fe batteries. Their new battery can be charged in about two minutes and discharged in 30 seconds. They envision application of the battery in electric vehicles. Their prototype is a one-volt battery that can power a flashlight.
The announcement was picked up by Agence France-Presse, whose article pointed out that Thomas Edison and fellow inventor Waldemar Jungner originally developed this type of battery more than one hundred years ago, with the intent of powering the electric cars of that era. Losing favor in the 1920s due to the decline of electric cars in favor of more powerful and versatile gasoline engine autos, the batteries maintained a position as a power source for railroads, mines, and other industries. Today they can be found associated with solar and wind power electricity storage.
Edison's first patent for his nickel-iron battery was issued as patent number US678,722 on July 16, 1901. It is fascinating reading, giving insight to the methodical experimentation that was in large part responsible for the successes of the "Wizard of Menlo Park." As an aside, Edison was one of the most prolific US inventors of all time. He was awarded 1,093 US patents, filed an estimated 500-600 patent applications that were not granted as patents or were abandoned, and received more than 1,200 non-US patents over the course of his 1868-1931 inventive career (source: Edison's Patents, Rutgers University, http://edison.rutgers.edu/patents.htm). Edison believed his nickel iron batteries could operate for 100 years. In 2011 US researcher Peter DeMar successfully rejuvenated to a usable state 85 year-old Ni-Fe cells manufactured by Edison. The accompanying photo shows Edison holding one of his Ni-Fe batteries.
Recent patenting activity in this portion of the patentECO Energy Index includes two US patent applications (12/603,945 filed October 22, 2009; and 12/910,247, filed October 22, 2010) from inventor Kan-Sen Chou and colleagues. These applications cover a manufacturing method for battery electrodes, and a composite electrode material -- both applications pertain to Ni-Fe battery technology.
As with many inventions in the clean tech arena, these are incremental improvements to old technologies to increase efficiencies, yields, streamline manufacturing methods, or reduce pollution and/or use of hazardous materials.