N/S co-doped carbon electrode material made from saponin pod skin for sodium ion battery with high performance

Waste biomass material derived carbon has become an important energy storage material which is easily available, inexpensive and environmentally friendly. However, it is a major challenge to develop ultra-high specific capacity and stable anode materials based on biomass carbon materials (BCMs). In this work, saponin pod skin was doped with thiourea through a simple hydrothermal process, followed by being sintered in one step to obtain simultaneously N and S elements co-doped porous carbon anode material for sodium ion batteries (SIBs). The active sites and layer spacing of the original pure BCM have been altered, which are conducive to the promotion of ion/electron transport. The half battery (Na/electrolyte/C) has a specific capacity of 259 mAh g‐⁻¹ at 0.1 A g⁻¹ maintaining a specific capacitance of 238 mAh g⁻¹ after 250 cycles, meanwhile it could reach a potential capacity of 239 mAh g⁻¹ at 1.0 A g⁻¹ which maintaining a specific capacity of 120 mAh g⁻¹ after 1000 cycles. This research provides new strategy for the development of novel biomass-derived carbon materials as anode materials for high-performance SIBs.