Exploration of biogenic nitrogen doped carbon microspheres derived from resorcinol-formaldehyde as anode for lithium and sodium ion batteries.

The study explores biogenic nitrogen doped carbon microspheres derived from resorcinol, formaldehyde (BNCMs), for battery application. Ureolytic bacteria were used to produce biogenic ammonia in the form of ammonium carbonate and ammonium bicarbonate. Copolymerization of resorcinol, formaldehyde and biogenic ammonia at 60-80 °C produces BNCMs. Elemental analysis evidences that the nitrogen-enriched carbon microspheres contain about 8% of nitrogen. The BNCMs anode exhibits appreciable reversible capacity and excellent rate performance in lithium ion batteries (LIBs) and sodium ion batteries (SIBs). In the case of LIBs, BNCMs anode exhibits an excellent stable specific capacity of 580 mAh g-1 with 97% of capacity retention even after 100 cycles without any significant capacity fading. Similarly, the observed capacity is as 102 mAh g-1 for 1000 cycles at a high rate current density of 1 A g-1 without any considerable capacity fade. In SIBs, BNCMs anode delivers a specific discharge and charge capacity of 405 and 195 mAh g-1 respectively. Further, prolonged cycles BNCMs anode exhibits a steady state progressive capacity of 170 mAh g-1 even after 100 cycles with steady state capacity. BNCMs thus evidence its suitability as high performance anode material for both LIBs and SIBs.