General synthesis of complex nanotubes by gradient electrospinning and controlled pyrolysis

Abstract

Nanowires and nanotubes have been the focus of considerable efforts in energy storage and solar energy conversion because of their unique properties. However, owing to the limitations of synthetic methods, most inorganic nanotubes, especially for multi-element oxides and binary-metal oxides, have been rarely fabricated. Here we design a gradient electrospinning and controlled pyrolysis method to synthesize various controllable 1D nanostructures, including mesoporous nanotubes, pea-like nanotubes and continuous nanowires. The key point of this method is the gradient distribution of low-/middle-/high-molecular-weight poly(vinyl alcohol) during the electrospinning process. This simple technique is extended to various inorganic multi-element oxides, binary-metal oxides and single-metal oxides. Among them, Li3V2(PO4)3, Na0.7Fe0.7Mn0.3O2 and Co3O4 mesoporous nanotubes exhibit ultrastable electrochemical performance when used in lithium-ion batteries, sodium-ion batteries and supercapacitors, respectively. We believe that a wide range of new materials available from our composition gradient electrospinning and pyrolysis methodology may lead to further developments in research on 1D systems.

Polyanion‐Type Electrode Materials for Sodium‐Ion Batteries

“…This special morphology played a vital role in improving the cycle stability and rate capability of the electrode due to the conductive network built up by the nanofibers ( Figure 16 a). In contrast, Mai and his group designed a gradient electrospinning and controlled pyrolysis method (Figure 16b) to synthesize various controllable 1D nanostructures and mesoporous nanotubes: pea‐like nanotubes and continuous nanowires 151. Owing to their large surface area, high conductivity, and robust structural stability, the prepared polyanion‐type compounds, Li 3 V 2 (PO 4 ) 3 and Na 3 V 2 (PO 4 ) 3 , exhibited excellent electrochemical performance both in Li‐ion batteries and Na‐ion batteries.…”

“…b) Schematics of the gradient electrospinning and controlled pyrolysis method: preparation process of mesoporous nanotubes and pea‐like nanotubes. Reproduced with permission 151. Copyright 2015, Nature Publishing Group.…”

Nanostructured electrode materials for lithium-ion and sodium-ion batteries via electrospinning

“…Compared with nanoparticles, these nanofibers showed improved cyclability due to enhanced charge transfer along the nanofibers and higher specific surface area of nanofibers. Moreover, Niu and co-workers [238] presented one facile strategy to fabricate mesoporous nanotubes via a gradient electrospinning and controlled pyrolysis process and enhanced the Na-ion storage performance of Na 0.7 Fe 0.7 Mn 0.3 O 2 mesoporous nanotubes. The formation of mesoporous nanotubes is based on the gradient of distribution of low-/middle-/high-molecular-weight PVA during electrospinning.…”

Multi-compartment centrifugal electrospinning based composite fibers

“…Co-axial electrospinning (CO-ES), centrifugal electrospinning (CES), fiber printing (2D and 3D) rotary jet-spinning are notable advances within this remit [12][13][14]. These developments have enabled multi-phase fiber composites and compartmentalization [15], ordered filamentous structures [16], Janus fiber systems [17] and high production rates [18]. It is noteworthy, technological advance is often driven by the underlying need or property requirement of an end application; and electrospinning (ES), and its various sister processes (i.e.…”