High-level N/P co-doped Sn-carbon nanofibers with ultrahigh pseudocapacitance for high-energy lithium-ion and sodium-ion capacitors

摘要

The development of high-energy lithium-ion and sodium-ion capacitors (LICs and SICs) is still a challenge due to the kinetics mismatch between the insertion/deinsertion anode and adsorption/desorption cathode. Here, high-level N/P-doped Sn-carbon nanofibers (Sn-NP-CNFs) were fabricated via an electro-spinning technique followed by pre-oxidization and carbonization. The N/P-doping increased the defects and carbon interlayer distance to inhibit the precipitation and volume expansion of the Sn and improve the Li/Na-adsorption, resulting in an ultrahigh pseudocapacitance and rate capability of the Sn-NP-CNF. An advanced LIC and SIC were composed of an activated carbon cathode and a Sn-NP-CNF anode. The LIC and SIC displayed ultrahigh energy densities (186.0 Wh kg(-1) and 134.6 Wh kg(-1)) and power densities (20.0 kW kg(-1) achieved at 22.2 Wh kg(-1)) with superior energy retentions (83.7% and 79.8% after 10,000 cycles at 5.0 A g(-1)). (C) 2020 Published by Elsevier Ltd.