Nitrogen-doped Porous Carbon Obtained from Silk Cocoon for High Performance Li-O-2 Batteries

Nitrogen-doped porous carbon obtained from silk cocoon (NCFC) was first used as cathodes for Li-O-2 batteries with ionic liquid in this paper. NCFC is made up of irregular bending slices and has a high specific discharge product of most Li-O-2 surface area of 2142.0 m(2) g(-1) which means numerous active sites for electrochemical reactions. The results show that NCFC based Li-O-2 battery has good cycle stability and high energy efficiency under different current density. In particular, NCFC based Li-O-2 batteries can work more than 400 cycles (500 mAh g(-1) at 0.20 mA cm(-2)) with the maximum overpotential less than 0.92 V, which is much better than super P based Li-O-2 batteries (188 cycles with overpotential up to 1.88 V) and many reported Li-O-2 batteries. The results show that NCFC is a very promising material for Li-O-2 batteries.