http://arxiv.org/abs/1203.0161
Self-Charged Graphene Battery Harvests Electricity from Thermal Energy of the Environment, Zihan Xu et al: "Moreover, the thermal velocity of ions can be maintained by the external environment, which means it is unlimited. However, little study has been reported on converting the ionic thermal energy into electricity. Here we present a graphene device with asymmetric electrodes configuration to capture such ionic thermal energy and convert it into electricity. (...) To exclude the possibility of chemical reaction, we performed control experiments... (...) In conclusion, we could not find any evidences that support the opinion that the induced voltage came from chemical reaction. The mechanism for electricity generation by graphene in solution is a pure physical process..."

http://arxiv.org/abs/1204.6688
"Graphene can collect energy from the ambient heat and convert it to electricity, which makes it an ideal candidate for the fabrication of self-powered devices. However, this technology is suffering the high cost, which limits the practical use of it. In this work, we demonstrated that the cost can be reduced by using low cost reduced graphene oxide (RGO), graphite electrodes and low cost glass substrates. The results showed that this technology can be of practical value for the "battery" industry."

Fifty years ago such a challenge to the second law of thermodynamics would have concerned primarily theoreticians and philosophers of physics (they would have gone mad with excitement) and to a lesser extent technologists. Nowadays theoreticians couldn't care less while philosophers of physics seem to have disappeared (almost no activity in the last two years or so).

Pentcho Valev