British scientists have created a new way to charge smartphones - using urine.Researchers have revealed a new system which transforms urine into electricity using a microbial fuel cell.Just over half a litre of urine is enough for six hours of charge time, which can power a smartphone for three hours.The units contain bacteria that breaks down the chemicals in urine, in the process releasing energy in the form of electricity which is stored on a capacitor within a fuel cell.'The microbial fuel cells (MFC) work by employing live microbes which feed on urine for their own growth and maintenance,' explained Professor Ioannis Ieropoulos.'The MFC is, in effect, a system which taps a portion of that biochemical energy.'This technology is about as green as it gets, as we do not need to utilise fossil fuels and we are effectively using a waste product that will be in plentiful supply.'