Nanostructure-modified in-situ synthesis of nitrogen-doped porous carbon microspheres (NPCM) loaded with FeTe2 nanocrystals and NPCM as superior anodes to construct high-performance lithium-ion capacitors

Lithium-ion capacitors (LICs) are the new generation of hybrid energy storage devices because they combine the advantages of both lithium-ion batteries and supercapacitors. This paper reports a threedimensional N-doped porous carbon microspheres (NPCM) prepared from polymers with aromatic skeletons, and in-situ growth of FeTe2 nanocrystals in carbon microspheres to form 3D network nanohybrid FeTe2@NPCM-2 composite. This porous microsphere structure facilitates the provision of sufficient room to buffer the large volume expansion effects of the FeTe2 cycle, the unique carbon matrix NPCM has numerous active sites, excellent electrical conductivity and stable tap density. Simultaneously, using biomass mung-bean shells as precursor to prepare hierarchical porous carbon (HPC) as cathode material of LIC, it exhibits a huge specific surface area (SSA) (2103.31 m(2)g(-1)), abundant micro-mesopores and possible oxygen-containing functional groups. The constructed LIC FeTe2@NPCM-2//HPC and NPCM// HPC have ultrahigh energy density (228.29 and 192.96 W h kg(-1)) and superior power density (10 and 10 kW kg(-1)) and good cycle retention rate. Hence, we hope that lithium-ion capacitors with transition metal tellurides as anodes have broad application prospects in the fields of new energy 3C electronic products and hybrid vehicles. (C) 2020 Elsevier Ltd. All rights reserved.