Phytic acid-derived Co2P/N-doped carbon nanofibers as flexible free-standing anode for high performance lithium/sodium ion batteries

Transition metal phosphides (TMPs) have been regarded as promising substitutes for lithium/sodium storage mainly due to the high capacity and good security. However, great challenges have to face in ultimate application, especially the problem of active substances uneven mixing in the electrode preparation process and structural collapse during circulation. Herein, we report a novel and facile strategy for synthesis 3D flexible conductive network hybrids of PA-derived Co2P nanoparticles encapsulated into N-doped carbon skeleton (Co2P/NC). The as-prepared Co2P/NC nanofibers acting as freestanding binder-free anode material can provide highly dispersed Co2P nanoparticles in cross-linked frameworks and effectively alleviate the structural collapse, bring about superior rate performance during repeated cycles. When applied in lithium-ion battery, the Co2P/NC nanofibers exhibit high capacity (1041.5 mA h g(-1) after 200 cycles at 100 mA g(-1)), excellent rate performance and long lifespan (retain a steady reversible capacity of 563.6 mA h g(-1) with CE similar to 100% after 1000 cycles at 10 A g(-1)). As for sodium-ion batteries, it also exhibits long-term stability and better reversible capacity (retains 132.3 mA h g(-1) after 2500 cycles at 1.0 A g(-1)). The SEM results show that the morphology of Co2P/NC after 1000th lithium (10 A g(-1))/sodium (1.0 A g(-1)) storage circulation can still maintain good integrity. (C) 2020 Elsevier B.V. All rights reserved.