Tin Nanodots Encapsulated in Porous Nitrogen‐Doped Carbon Nanofibers as a Free‐Standing Anode for Advanced Sodium‐Ion Batteries

Abstract

Ultrasmall Sn nanodots (1-2 nm) are homogeneously encapsulated in porous N-doped carbon nanofibers using a simple and scalable electrospinning method. The composite nanofibers weave into flexible free-standing membrane and can be directly used as binder- and current collector-free anode for Na-ion batteries, exhibiting excellent electrochemical performance with high reversible capacity, exceptional rate capability, and ultralong cycle life.

Metallic Sn‐Based Anode Materials: Application in High‐Performance Lithium‐Ion and Sodium‐Ion Batteries

“…People have varied the carbon precursors to produce the carbon matrix, including micromolecular organics,22, 26, 49, 50, 52, 56 polymer,6, 53, 57, 58, 59 saccharides,48, 51, 60, 61, 62 resins,55, 63, 64 graphene,65, 66, 67 etc. Derrien et al49 reported a synthesis of nano‐Sn (with a small amount of SnO 2 ) embedded in a carbon matrix.…”

“…Ultrasmall Sn particles (even Sn quantum dots) are usually obtained when N‐doped carbon is used as the matrix. N‐doping can add defects in the carbon, which is favorable as it increases the distribution density of Sn 57, 68. The interfacial Sn—N—C and/or Sn—O—C bonds probably form between Sn and N‐doped carbon and pin the Sn particles to the carbon, as a result, the aggregation of Sn is thoroughly inhibited 68.…”

“…Moreover, the intertwined 1D network structures can promote the charge‐transfer process and improve rate performance. Up to now, many 1D Sn‐based materials have been fabricated to be applied as anodes, such as 1D nanowires,19, 57, 59, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155 1D nanotubes,156, 157, 158, 159, 160 and 1D nanoarrays,5, 161, 162, 163, 164, 165, 166, 167 etc.…”

“…As shown in Figure 14 a, Sn nanodots (1–2 nm) finely encapsulated in porous N‐doped carbon nanofibers was prepared by Liu et al57 using the electrospinning technique. These nanofibers could be used as current collector‐ and binder‐free anodes in SIBs.…”

Flexible Electrodes for Sodium‐Ion Batteries: Recent Progress and Perspectives

“…When evaluated as half cells, the NVP/rGO paper-like cathode delivered a reversible capacity of 113 mA h g −1 at 100 mA g −1 and high capacity retention of ≈96.6% after 120 cycles, and the Sb/rGO paper-like anode gave a highly reversible capacity of 612 mA h g −1 at 100 mA g −1 and an excellent rate capacity up to 30C. Moreover, the Na-ion full cell assembled by coupling a Sb/rGO anode and an NVP/rGO cathode was able to deliver a reversible capacity of 400 mA h g −1 after 100 cycles at 100 mA g −1 and had the ability to power a Carbon nanofibers Electrospinning and carbonization 50 mA h g −1 at 1 A g −1 ≈200 mA h g −1 after 100 cycles at 0.1 A g −1 [56] Carbon nanofibrous webs Electrospinning and carbonization 80 mA h g −1 at 1 A g −1 247 mA h g −1 after 200 cycles at 0.1 A g −1 [57] Porous carbon nanofibers Electrospinning and carbonization 40 mA h g −1 at 20 A g −1 140 mA h g −1 after 1000 cycles at 0.5 A g −1 [58] Nitrogen-doped carbon nanofibers Electrospinning, imidation, and carbonization 154 mA h g −1 at 15 A g −1 210 mA h g −1 after 7000 cycles at 5 A g −1 [59] Graphene@porous carbon nanofibers Electrospinning and carbonization 261.1 mA h g −1 at 10 A g −1 330 mA h g −1 after 1000 cycles at 2 A g −1 [60] Sb@carbon fibers Electrospinning and carbonization 88 mA h g −1 at 6 A g −1 350 mA h g −1 after 300 cycles at 0.1 A g −1 [61] CuO@carbon nanofibers Electrospinning and carbonization 250 mA h g −1 at 5 A g −1 401 mA h g −1 after 500 cycles at 0.5 A g −1 [62] MoS 2 @carbon nanofibers Electrospinning and carbonization 89 mA h g −1 at 5 A g −1 283.9 mA h g −1 after 600 cycles at 0.1 A g −1 [63] Sn@nitrogen-doped carbon nanofiber Electrospinning and carbonization 450 mA h g −1 at 10 A g −1 483 mA h g −1 after 1300 cycles at 2 A g −1 [64] www.advmat.de www.advancedsciencenews.com commercial light-emitting diode (LED), even when the cell was subjected to bending (Figure 2b-d). It is obvious that this work shows a high capacity, good cycling stability, and excellent rate performance for both half cells and full cells, which provides an effective route to bendable and high-performance electrode materials for next-generation flexible SIBs.…”