No abstract

The aim of the study involves accelerating ultrafast electrochemical behavior of lithium‐ion batteries (LIBs) by proposing hierarchical core/shell heterostructure of carbon nanofiber (CNF)/3D interconnected hybrid network with nanocarbon and fluorine‐doped tin oxide (FTO) nanoparticles (NPs) via a one‐pot process of horizontal ultrasonic spray pyrolysis deposition. This is constructed via a pyrolysis reaction of ketjen black forming 3D interconnected FTO NPs covered with nanocarbon network on CNF. It offers fast electrical conductivity to the overall electrode with improved Li ion diffusion due to decreased size effect and relaxed structural variation of FTO NPs via nanocarbon network, leading to high discharge capacity (868.7 mAh g−1 after 100 cycles) at 100 mA g−1 and superior rate capability. Nevertheless, at extremely high current density (2000 mA g−1), significant ultrafast electrochemical performances with reversible discharge capacity (444.4 mAh g−1) and long‐term cycling retention (89.9% after 500 cycles) are noted. This is attributed to the novel effects of 3D interconnected hybrid network accelerating receptive capacity of Li ions into the FTO NPs via nanocarbon network, delivery of formed Li ions and electrons by hybrid network with FTO NP and nanocarbon, and prevention of FTO NP pulverization from CNFs via nanocarbon network. Therefore, the proposed heterostructure holds significant promise for effective development of ultrafast anode material for enhancing the practical applications of LIBs.

No abstract

No abstract

No abstract

Designing an interfacial architecture between the current collector and electrode plays a serious role in developing the specific capacity with cycling stability of lithium-ion batteries (LIBs). Consequently, an original approach to enhance the structure of the interface between the current collector and electrode is necessary. Thus, we developed a novel interface architecture based on carbon quantum dots (CQDs)-laminated on a stepped porous Al (SP-Al) current collector to attain stable and ultrafast-discharge LIBs and CQD-SP-Al for application as LIB cathodes. To this end, the electrochemical etching and ultrasonic spray coating methods were employed. The cathode assembled with CQD-SP-Al displayed the adhesion enhancing, an increased redox reaction kinetics, and the magnificent interfacial stability of the current collector//electrode interface because of the increased surface roughness, stepped pores with N-doped CQD, and uniform CQD lamination layer. The resultant cathode with CQD-SP-Al showed an enhanced specific capacity of 78.2 mAh/g and capacity retention of 92.6% at a high C-rate of 10C after 500 cycles. This great cycling stability is due to an expanded interfacial contact area of current collector// electrode with improved adhesion, as well as to the CQD lamination layer, while the excellent ultrafast discharge capacity is ascribed to the risen number of charge supplying/collecting sites, the stepped porous structure, and the highly conductive N-doped CQD lamination layer.

Summary Combining a high‐capacity material possessing a core@shell structure with a carbon material is a powerful tactic for reinforcing the performance of Li‐ion battery (LIB) anodes. As an efficient and simple approach to obtain tin(II) sulfide (SnS) with ultrafast lithium‐storage capability and cycling stability, we propose the hierarchical core@shell structure of carbon nanofibers@SnS nanotubes (CNF@SnSNTs) covered with S‐doped carbon via a one‐pot carbonization by harnessing the Kirkendall effect of camphene and sulfurization of SnO2 by L‐cysteine. This hierarchical core@shell structure contains mesoporous carbon nanofibers (CNFs) that reduce the Li‐ion diffusion pathway, SnS nanotubes (NTs) that expand the active site, and a S‐doped carbon layer at the faces of the SnS NTs that promotes the electrical conductivity and inhibits volume expansion of SnS. Therefore, a CNF@SnSNT‐C7 electrode achieves superb ultrafast electrochemical performance (528.1 mAh/g under a current density of 2000 mA/g), high specific capacity (2218.2 mAh/g under a current density of 100 mA/g), and an ultrafast cycling stability of 92.9% after 500 cycles under a current density of 2000 mA/g. These performance improvements are resulted from the synergistical effect of mesoporous CNFs, SnS NTs, and S‐doped carbon layer. Therefore, CNF@SnSNT is potential anode material for LIBs having superior Li‐storage capability.

No abstract