Synthesis of Uniquely Structured Yolk–Shell Metal Oxide Microspheres Filled with Nitrogen‐Doped Graphitic Carbon with Excellent Li–Ion Storage Performance

Abstract

Novel structured composite microspheres of metal oxide and nitrogen-doped graphitic carbon (NGC) have been developed as efficient anode materials for lithium-ion batteries. A new strategy is first applied to a one-pot preparation of composite (FeO -NGC/Y) microspheres via spray pyrolysis. The FeO -NGC/Y composite microspheres have a yolk-shell structure based on the iron oxide material. The void space of the yolk-shell microsphere is filled with NGC. Dicyandiamide additive plays a key role in the formation of the FeO -NGC/Y composite microspheres by inducing Ostwald ripening to form a yolk-shell structure based on the iron oxide material. The FeO -NGC/Y composite microspheres with the mixed crystal structure of rock salt FeO and spinel Fe O phases show highly superior lithium-ion storage performances compared to the dense-structured FeO microspheres with and without carbon material. The discharge capacities of the FeO -NGC/Y microspheres for the 1st and 1000th cycle at 1 A g are 1423 and 1071 mAh g , respectively. The microspheres have a reversible discharge capacity of 598 mAh g at an extremely high current density of 10 A g . Furthermore, the strategy described in this study is generally applied to multicomponent metal oxide-carbon composite microspheres with yolk-shell structures based on metal oxide materials.

A Double‐Buffering Strategy to Boost the Lithium Storage of Botryoid MnOx/C Anodes

“…78‐0424). Second, without the high‐temperature annealing procedure in N 2 , both Mn‐BTC spheres with and without encapsulation developed the concentric ring morphology (Figure e, Figure S11c, Supporting Information) during preoxidation, which is likely due to gradient oxygen diffusion and Oswald ripening . In air under 300 °C, the oxygen diffuses into the Mn‐BTC sphere in a gradient fashion with the diffusion rate much faster than the outward migration of Mn species, which are oxidized into Mn 2 O 3 (Figure S11e, Supporting Information, JCPDS No.…”

Metal–Organic Gel‐Derived FexOy/Nitrogen‐Doped Carbon Films for Enhanced Lithium Storage

“…The XPS peak of N 1s contains three different bonding environments. Three primary peaks around binding energies of 398.6, 399.9, and 400.8 eV are widely proposed to be assigned to pyridinic, pyrrolic, and graphitic N, respectively (Figure S7, Supporting Information) …”

A Review: Enhanced Anodes of Li/Na-Ion Batteries Based on Yolk–Shell Structured Nanomaterials

“…Fortunately, nanosized TiO 2 was thinned to a few nanometers while had sufficient mechanical strength. This Al@TiO 2 YS nanosphere possessed a high rate of 1200 and 650 mAh g −1 at 1 C and 10 C, respectively, after the same 500 cycles and realized a robust 99.2% Coulombic efficiency at 1 C. Kim et al [ 115 ] filled structurally stable nitrogen-doped graphitic carbon in YS FeO x sphere. It showed the excellent capacity performance of 1071 mAh g −1 for 1000 cycles and high rate capacity of 598 mAh g −1 at 10 A g −1 .…”