Ultrafine Amorphous SnO_x Embedded in Carbon Nanofiber/Carbon Nanotube Composites for Li‐Ion and Na‐Ion Batteries

Abstract

Core–shell‐structured, ultrafine SnOx/carbon nanofiber (CNF)/carbon nanotube composite films are in situ synthesized by electrospinning through a dual nozzle. The carbon shell layer functions as a buffer to prevent the separation of SnOx particles from the CNF core, allowing full utilization of high‐capacity SnOx in both Li‐ion and Na‐ion batteries. The composite electrodes reveal an anomalous Li‐ and Na‐ion storage mechanism where all the intermediate phases, like LixSn and NaxSn alloys, maintain amorphous states during the entire charge/discharge process. The uniform dispersion on an atomic scale and the amorphous state of the SnOx particles remain intact in the carbon matrix without growth or crystallization even after 300 cycles, which is responsible for sustaining excellent capacity retention of the electrodes. These discoveries not only shed new insights into fundamental understanding of the electrochemical behavior of SnOx electrodes but also offer a potential strategy to improve the cyclic stability of other types of alloy anodes that suffer from rapid capacity decays due to large volume changes.

Synthesis and Electrochemical Performance of SnOx Quantum Dots@ UiO-66 Hybrid for Lithium Ion Battery Applications

“…The corresponding Coulombic efficiency of the SnO x @Zr-MOF electrode is also displayed in Figure d, and the average can be up to 97%. Simultaneously, the cycling retention and capacity are clearly better than some of the previous reports, and their synthesis methods are much more complicated and energy-intensive. − Interestingly, an increasing trend in capacity is observed during the later cycles from the 65th to the 90th cycle, as shown in Figure d. The enhanced capacity may be ascribed to the increase in the accessibility of the Li ions in the SnO x @Zr-MOF material during cycling, which results in an increased accommodation behavior for lithium. ,, The electrochemical performance of the SnO x -based materials compared to that in the previous studies is shown in Table S1.…”

Carbon framework microbelt supporting SnO x as a high performance electrode for lithium ion batteries

“…Meanwhile the irreversible capacity (790 mAh g −1 ) [53][54][55][56] is mainly attributed to the formation of the SEI layer. The detailed cycling performance and Coulombic efficiency of the sample are depicted in figure 3(c), it can be seen that the CFM-SnO x electrode exhibits a high capacity of 768 mAh g −1 after 200 cycles, which is more than twice higher than that of the commercial graphitic anode (372 mAh g −1 ) and superior than previously reported SnO x /C nanofiber electrode [30,[57][58][59][60][61]. The slight increase of the capacity after about 100 cycles may be attributed to the growing of polymeric gel-like films, which is promoted by Sn nanoparticles [62,63].…”

Confined Porous Graphene/SnOx Frameworks within Polyaniline-Derived Carbon as Highly Stable Lithium-Ion Battery Anodes

“…Two redox peaks observed at about 0.01 V (cathodic scan) and 0.52 V (anodic scan) represent Li + insertion/extraction into/from carbonaceous matrix and alloying/dealloying with Sn, respectively. The peak around 1.2 V in the first anodic scan is mostly ascribed to partial reversible reaction of SEI and slight oxidation of Sn during the charge–discharge processes . The curve of the second cycle is similar to that of the third one, indicating the highly reversible performance. , Figure b describes the selected galvanostatic charge/discharge voltage profiles of pG/SnO x /C electrode at a current density of 100 mA g –1 between 0.01 and 3 V. The electrode delivers high initial discharge/charge capacities of 1787/946 mAh g –1 , corresponding to a Coulombic efficiency (CE) of about 53%.…”