Facile Approach To Prepare Multiple Heteroatom-Doped Carbon Material from Bagasse and Its Applications toward Lithium-Ion and Lithium–Sulfur Batteries

The constant search for cost-effective and high-performance materials for Li-ion batteries (LIBs) has increased with time. Here, we synthesized low-cost multi-heteroatom co-doped carbon from biowaste bagasse [N, S, and O co-doped carbon (NSOC-10)]. We also investigated the influence of heteroatom doping in the carbon matrix and its effect on the electrochemical properties when used in Li-ion and Li–S batteries. Interestingly, the NSOC-10 sample shows a capacity of 574 mAh g–1 even after 1000 cycles, which is much higher than the theoretical capacity of a traditional graphite anode (372 mAh g–1), while undoped carbon degrades quickly (pristine bagasse) and displays only 26.6% capacity retention within 250 cycles. The excellent capacity retention of NSOC-10 could be attributed to a highly porous carbon matrix that tends to increase Li+ percolation, shorten the Li+ diffusion path, and boost the lithium-ion storage capability. Further, we studied the use of the heteroatom-doped NSOC-10 carbon matrix as a carbon host for the sulfur cathode in a Li–S battery. Indeed, the Li–S cell showed an initial capacity of 1200 mAh g–1 with a capacity retention of 79% by the end of 250 cycles and maintained high coulombic efficiency of >99%. This is attributed to the heteroatom (N, S, and O) doping in the activated carbon scaffold that resulted in better electrode wettability, high Li+ diffusion rate, and good electron conductivity of the carbon matrix, and this polar carbon adsorbs polar polysulfides through polar–polar interactions and maintains its capacity. Hence, the designed cost-effective co-doped NSOC-10 was identified to be a promising candidate as an anode material in LIBs and also as a potential sulfur host in Li–S batteries.