Cheese-like bulk carbon with nanoholes prepared from egg white as an anode material for lithium and sodium ion batteries

Cheese-like bulk carbon with nanoholes has been successfully fabricated from egg white via a simple annealing method by using distilled water as a green clean “corrosive agent”. X-ray diffractions and SEM images show the decomposition product of boiled egg white after annealing is bulk carbon, containing NaCl and KCl with a trace amount of nitrogen doping. After ultrasonic washing and centrifugation, the distilled water removed the NaCl and KCl nanocrystals from the bulk carbon completely and retained empty spaces, which eventually leads to the formation of a cheese-like structured bulk carbon with nanoholes. Our electrochemical tests show this cheese-like bulk carbon with nanoholes has a high specific capacity and good cycling performance and rate stability when evaluated as an anode material for lithium-ion batteries. Meanwhile, the electrochemical performances as an anode material for a sodium-ion battery are also displayed for comparison.