The battery is one of those ubiquitous devices that most of us use in our everyday lives and never think much about. Everything from your car to your notebook to your cell phone uses a battery of some sort. With the need to move to greener methods to power vehicles, much research is being conducted on technologies that will make batteries better.
A group of researchers from MIT has announced that they were able to construct a battery using a common type of virus that is not harmful to humans called a bacteriophage. Angela Belcher, lead researcher on the team said that the new battery could one day be used to power electronics and even electric cars.
The battery was described in the April 2 online edition of Science. According to the researchers, the battery could be produced cheaply and would be environmentally benign thanks to the fact that the process can be produced at below room temperature and requires no harsh organic solvents and the materials used in the battery construction are non-toxic.
Materials used in traditional lithium-ion batteries can’t claim to be environmentally friendly. In a traditional battery, the negatively charged anode is typically made form graphite and the positively charged cathode is usually cobalt oxide or lithium-ion phosphate.
MIT reports that three years ago, Belcher led a team that was able to construct an anode from viruses. The viruses were coaxed into coating themselves with cobalt oxide and gold. After the coating process, the viruses assembled themselves into a nanowire.
The latest announcement comes after the team was able to complete what the researchers say is the more complicated process of building a powerful cathode to pair up with the anode. Cathodes are reportedly more difficult to build because they have to be highly conducting, but most materials appropriate for a cathode are highly insulating.
Members of the research team were able to create the cathode by genetically engineering viruses that coat themselves with iron phosphate and then grab carbon nanotubes to create a network of highly conductive material.
The viruses are engineered to bind to specific materials only. The carbon nanotubes in the team's cathode and each iron phosphate nanowire can be electrically connected to a conducting carbon nanotube network allowing electrons to travel through the nanotube networks and transfer energy in a short time.
The researchers say that adding the carbon nanotubes to the battery adds very little weight and increased the cathode’s conductivity. The researchers say that in experiments the cathode material could be charged and discharged at least 100 times before losing its capacity. The team points out that 100 cycles is less than current lithium-ion batteries, but the virus-powered batteries are expected to last longer between charges.
A prototype battery was packaged into a standard coin battery form factor and used to power an LED light. The prototype was shown to President Obama when MIT President Susan Hockfield talked to Obama about the need for funding to advance clean-energy technologies.
The team says their next plan is to create a battery with materials offering higher voltage and capacitance like manganese phosphate and nickel phosphate. Once the next generation of virus battery is ready, they could go into commercial production. Researchers at MIT working on another project announced last month that they created a battery that could recharge in seconds.
quote: Energy density is more of a functional issue
quote: Existing batteries are essentially toxic waste once you are done with them
quote: Li-Sulfur has a slightly better energy density but is still the the testing phases. Li-ion with nano-material anodes and cathodes are possible and are being researched which could produce up to 10x better density I believe.