High energy density lithium-ion capacitor enabled by nitrogen-doped amorphous carbon linked hierarchically porous Co3O4 nanofibers anode and porous carbon polyhedron cathode

Abstract

Lithium-ion capacitors (LICs) are emerging as progressive energy storage systems with high energy density, high power output, and a long cycle life span. The key to constructing LICs with high performances is alleviating the dynamics mismatch between the faradic anode and capacitor-type cathode. Herein, nitrogen-doped amorphous carbon linked hierarchically porous Co 3 O 4 nanofibers (NAC- l -Co 3 O 4 NFs) were prepared by electrospinning strategy, where the amorphous carbon can mitigation the volume variation of Co 3 O 4 during the lithiation/delithiation process, while the hierarchically porous structure provides effective channels and exposes more active sites for fast electron transfer and Li + storage. The delicate structure endows NAC- l -Co 3 O 4 NFs with remarkable rate capacity and robust cycling durability. Furthermore, nitrogen-doped carbon polyhedron (NPCP) is prepared for the cathode, displaying superior rate performances and cycling stability. As a result, by assembling the NAC- l -Co 3 O 4 //NPCP LICs, a high energy density of 296 Wh kg −1 and a high output of 11750 W kg −1 is delivered. Additionally, the LIC devices display excellent cycle lifespan (80% capacity retention after 10000 cycles at 1 A g −1 ). • Nitrogen-doped amorphous carbon-linked Co 3 O 4 1D nanostructured anode (NAC-l-Co 3 O 4 NFs) is fabricated via electrospinning technique. • The 1D nanofibers interlink into a 3D network further facilitating ions/electrons transmittability. • The LIC assembled with NAC- l -Co 3 O 4 anode shows an ultrahigh energy density (357 Wh kg) and excellent cycling stability.