Golden Bristlegrass‐Like Hierarchical Graphene Nanofibers Entangled with N‐Doped CNTs Containing CoSe₂ Nanocrystals at Each Node as Anodes for High‐Rate Sodium‐Ion Batteries

Abstract

Recently, transition-metal chalcogenides (TMCs) have widely been studied as anode materials for sodium-ion batteries (SIBs) because of their structural characteristics and unusual chemical, physical, and electronic properties. [1-3] However, their practical energy-storage performance is far below the Golden bristlegrass-like unique nanostructures comprising reduced graphene oxide (rGO) matrixed nanofibers entangled with bamboo-like N-doped carbon nanotubes (CNTs) containing CoSe 2 nanocrystals at each node (denoted as N-CNT/rGO/CoSe 2 NF) are designed as anodes for high-rate sodium-ion batteries (SIBs). Bamboo-like N-doped CNTs (N-CNTs) are successfully generated on the rGO matrixed nanofiber surface, between rGO sheets and mesopores, and interconnected chemically with homogeneously distributed rGO sheets. The defects in the N-CNTs formed by a simple etching process allow the complete phase conversion of Co into CoSe 2 through the efficient penetration of H 2 Se gas inside the CNT walls. The N-CNTs bridge the vertical defects for electron transfer in the rGO sheet layers and increase the distance between the rGO sheets during cycles. The discharge capacity of N-CNT/ rGO/CoSe 2 NF after the 10 000th cycle at an extremely high current density of 10 A g −1 is 264 mA h g −1 , and the capacity retention measured at the 100th cycle is 89%. N-CNT/rGO/CoSe 2 NF has final discharge capacities of

Heterostructured SnSe2-CoSe2 microspheres embedded in reduced graphene oxides as an anode material with high sodium storage

“…According to the fitting results, it is noteworthy that the peak at 484.98 eV relating to Sn 2+ accounts for a very small section [47]. Figure 4 d presents the high-resolution Co 2p spectrum; the two peaks located at 777.88 and 796.78 eV are ascribed to Co 3/2 and Co 1/2 , certificating the existence of Co 2+ [48].…”

Nanostructured Graphene Oxide-Based Hybrids as Anodes for Lithium-Ion Batteries

“…The N-CNT/rGO/CoSe 2 hybrid, tested as anode material for sodium-ion batteries (SIBs), delivers a discharge capacity of 264 mAh g −1 after 10,000 cycles at a high current density of 10 A g −1 , and the capacity retention of 89% at the 100th cycle. The rate capability tests show discharge capacities of 395, 263, and 151 mAh g −1 at 1, 10, and 20 A g −1 current densities, respectively [529].…”

The Multicomponent Synergistic Effect of Sandwich Structure Hierarchical Nanofibers for Enhanced Sodium Storage

“…The abundant lattice mismatch and defects formed at heterogeneous interfaces change the reaction kinetics and long-range disorder, further affect the transport behavior of carriers. [21][22][23] The diverse redox potentials and out-of-step electrochemical reactions of different components alleviate volumetric strains during intercalation/extraction processes of Na + . [23] Constructing hierarchical micro/nanostructures as anodes for sodium ion batteries is an important approach for exploiting efficient energy storage devices.…”