Free-standing single-walled carbon nanotube/SnO2 anode paper for flexible lithium-ion batteries

Abstract

Free-standingsingle-walledcarbonnanotube/SnO 2 (SWCNT/SnO 2 ) anodepaper was prepared by vacuum filtration of SWCNT/SnO 2 hybrid material which was synthesized by the polyol method. From field emission scanning electron microscopy and transmission electron microscopy, the CNTs form a three-dimensional nanoporous network, in which ultra-fine SnO 2 nanoparticles, which had crystallite sizes of less than 5 nm, were distributed, predominately as groups of nanoparticles on the surfaces of singlewalled CNT bundles. Electrochemical measurements demonstrated that the anodepaper with 34 wt.% SnO 2 had excellent cyclic retention, with the high specific capacity of 454 mAh g −1 beyond 100 cycles at a current density of 25 mA g −1 , much higher than that of the corresponding pristine CNT paper. The SWCNTs could act as a flexible mechanical support for strain release, offering an efficient electrically conducting channel, while the nanosized SnO 2 provides the high capacity. The SWCNT/SnO 2 flexible electrodes can be bent to extremely small radii of curvature and still function well, despite a marginal decrease in the conductivity of the cell. The electrochemical response is maintained in the initial and further cycling process. Such capabilities demonstrate that this model hold great promise for applications requiring flexible and bendable Li-ion batteries. AbstractFree-standing single-walled carbon nanotube/SnO 2 (SWCNT/SnO 2 ) anode paper was prepared by vacuum filtration of SWCNT/SnO 2 hybrid material which was synthesized by the polyol method. From field emission scanning electron microscopy and transmission electron microscopy, the CNTs form a three-dimensional nanoporous network, with ultrafine SnO 2 nanoparticles, which had crystallite sizes of less than 5 nm, were distributed, predominately, as groups of nanoparticles on the surfaces of parallel packets or bunches of single walled CNTs. Electrochemical measurements demonstrated that the anode paper with 31 wt.% of SnO 2 had excellent cyclic retention, with the high specific capacity of 454 mAh g -1 beyond 100 cycles at a current density of 25 mA g -1 , much higher than that of the corresponding pristine CNT paper. The SWCNTs could act as a flexible mechanical support for strain release, offering an efficient electrically conducting channel, while the nanosized SnO 2 provides the high capacity. The SWCNT/SnO 2 flexible electrodes can be bent to extremely small radii of curvature, and still function well, despite a marginal decrease the conductivity of the cell. After bending, the conductivity of the cell is 4.8 × 10 -4 S·m -1 , which is slightly lower than that of the cell that was no subjected to bending (5.2 × 10 -4 S·m -1 ). The electrochemical response is maintained in the initial and further cyclingprocess. Such capabilities demonstrate this model hold great promise for application requiring flexible and bendable Li-ion batteries. 3 IntroductionThere has been more interest recently in flexible and bendable energy storage devices, especially in the field...

A germanium/single-walled carbon nanotube composite paper as a free-standing anode for lithium-ion batteries

“…1(a). The diffraction peaks for SWCNTs at 2θ of 23° and 45° could be indexed as the (002) and (101) reflections [16]. The diffraction peak of the (002) diffraction is related to the typical random arrangement of CNTs, with a d 002 of 0.38 nm calculated based on Bragg's equation.…”

“…Composites with SWCNTs, such as Si/SWCNT [12,13], Fe 2 O 3 /SWCNT [14,15], SnO 2 /SWCNT [16], and MnO x /SWCNT [17] have been reported as paper anode materials. Although good electrochemical performances achieved by these already studied composite paper anodes were attractive, most of the preparation routes are too complicated or require high reaction temperature, limiting their industrial implementation.…”

High‐Loading Nano‐SnO2 Encapsulated in situ in Three‐Dimensional Rigid Porous Carbon for Superior Lithium‐Ion Batteries

“…Such ac ommon electrochemical phenomenonc an be attributed to decomposition of the electrolyte and subsequent formation of the solid electrolyte interphase (SEI) filmo nt he large surface areas of OMC during the first cycle. [48,49] As indicated in Figure 3b, SnO 2 /OMC shows higher specific discharge and chargec apacities of 1450 and 843 mAh g À1 in the first cycle,r espectively, corresponding to an improved Coulombic efficiency of 58.1 % in comparison with that of pristine OMC. Accordingly,e xs itu loading of SnO 2 NPs on the OMC framework results in an in- Figure 3c.F igure3dc ompares the cycling performance of these three samples.…”

Spectroelectrochemistry at free-standing carbon nanotubes electrodes

“…In particular, free-standing CNT electrodes represent an innovative factor for very attractive applications, such as electrochemical sensors [15,16], laser absorber [16], gas flowmeter [16], gas heater [16], supercapacitors [17], in thermoacoustic applications [18] and in batteries [19,20]. Different methods have been developed for the fabrication of free-standing CNT films, the most important routes being CVD [16,21,22] and vacuum-filtration [23,24], although others such as the solvent evaporation method [25] have also been used.…”