N-carbon from waste tea as efficient anode electrode material in lithium ion batteries

Nanostructured carbon having nitrogen as heteroatom was synthesized from waste tea, a cheap and abundant waste generated around the world. The synthesis process is simple, environmental being one-step pyrolysis in inert atmosphere. The carbon synthesized at 800°C (WTC-800) has mesh like morphology with abundantmesopores. The BET analysis reveals mesoporous nature with specific surface area of 384 m²g^-1. The porous morphology was found to diminish with increase in pyrolysis temperature. XPS analysis reveals the presence of 1.8-2.5% N-content with predominantly graphitic-N. As-synthesized carbons are investigated as anode material for Li-ion battery. The mesoporous structure and N doping endowed WTC-800 with high reversible capacity up to 567 mAhg^-1 at 0.1 C rate, much higher than commercial graphite based anode. Furthermore, the charge discharge process of WTC-800 is not only stable and reversible at high current rate (49% retention at 1 C rate), but also stable up to 100 cycles (78% retention). Relation of capacitive performance with surface area, porosity and N doping is studied and explained promptly. Combined with easy synthesis method, mesoporous structure, inherent N content with abundantly available waste precursor made this carbon material as suitable candidate for electrode materials in Li ion battery applications.