Structural engineering of tin sulfides anchored on nitrogen/phosphorus dual-doped carbon nanofibres in sodium/potassium-ion batteries

Na/K-ion batteries (SIBs/PIBs) owing to their low cost, earth abundance, appropriate redox potential and comparable electrochemical performance, have gained ever-growing attention. Nevertheless, it remains a major challenge for high performance of SIBs/PIBs applications. Herein, with the assistance of waste chlorella as the reactor and phosphorous source, we designed few-layered tin sulfides immobilized on nitrogen and phosphorus dual-doped carbon nanofibres (SnSx-N/P-CNFs). The characterization and DFT calculation results demonstrate that N/P co-doping is expected to favour the distribution of electron density and strengthen ion reaction kinetics, which can enhance the Na+/K+ storage performance. As expected, as an anode material for SIBs, the SnSx-N/PeCNF electrode displays an impressive capacity (522 mAh g(-1) after 50 cycles at 0.1 A g(-1)) and promising long-life cycling performance (214 mAh g(-1) up to 32,000 cycles at 10 A g(-1)). Moreover, it also exhibits exceedingly impressive potassium-ion storage performance (468 mAh g(-1) at 0.1 A g(-1) after 100 cycles and 170 mAh g(-1) exceed 10,000 cycles at 5 A g(-1)), which is the one of the optimal long-cycle properties reported for Sn-based anode for PIBs to date. Our work provides a reference for using biomass algae as the nitrogen and phosphorous source in constructing energy storage materials. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

In this study, waste chlorella was used as a reactor and phosphorous source to design few-layered tin sulfides immobilized on nitrogen and phosphorus dual-doped carbon nanofibres. The material exhibited impressive sodium/potassium ion storage performance and promising long-life cycling performance, suggesting its great potential for sodium/potassium-ion battery applications.