Octahedral Tin Dioxide Nanocrystals Anchored on Vertically Aligned Carbon Aerogels as High Capacity Anode Materials for Lithium-Ion Batteries

Abstract

A novel binder-free graphene - carbon nanotubes - SnO2 (GCNT-SnO2) aerogel with vertically aligned pores was prepared via a simple and efficient directional freezing method. SnO2 octahedrons exposed of {221} high energy facets were uniformly distributed and tightly anchored on multidimensional graphene/carbon nanotube (GCNT) composites. Vertically aligned pores can effectively prevent the emersion of “closed” pores which cannot load the active SnO2 nanoparticles, further ensure quick immersion of electrolyte throughout the aerogel, and can largely shorten the transport distance between lithium ions and active sites of SnO2. Especially, excellent electrical conductivity of GCNT-SnO2 aerogel was achieved as a result of good interconnected networks of graphene and CNTs. Furthermore, meso- and macroporous structures with large surface area created by the vertically aligned pores can provide great benefit to the favorable transport kinetics for both lithium ion and electrons and afford sufficient space for volume expansion of SnO2. Due to the well-designed architecture of GCNT-SnO2 aerogel, a high specific capacity of 1190 mAh/g with good long-term cycling stability up to 1000 times was achieved. This work provides a promising strategy for preparing free-standing and binder-free active electrode materials with high performance for lithium ion batteries and other energy storage devices.

Hierachical Aerogel-Supported Cu–Sn–Ox Solid Solutions for Highly Selective CO2 Electroreduction and Zn–CO2 Batteries

“…It is observed that Cu–Sn–O x /rGO exhibits 42.6% O-vacancies, whereas SnO 2 /rGO demonstrates 33.8% O-vacancies. The high-resolution XPS spectrum of Sn 3d orbitals in Figure d displays two distinct peaks at 495.7 and 487.3 eV, which can be attributed to the 3d 3/2 and 3d 5/2 peaks in the binding energy between Sn 4+ and O. , The disparity in binding energy between the two peaks is 8.4 eV, which aligns with the comparison between the 3d 3/2 and 3d 5/2 peaks of Sn 4+ in SnO 2 . − It has been observed that the binding energies of the Sn 3d 5/2 and 3d 3/2 peaks shift from 495.7 and 487.3 eV in SnO 2 /rGO to 495.1 and 487.0 eV in Cu–Sn–O x /rGO. This shift is due to the differing electronegativities of Cu (1.90) and Sn (1.96), leading to a greater transfer of electrons from Cu 2+ to Sn 4+ in Cu–Sn–O x /rGO.…”

Synthesis of Metal Oxide/Carbon Nanofibers via Biostructure Confinement as High-Capacity Anode Materials

“…Two distinct peaks at 0.7 and 0.2 V appear during the initial cycle but vanish in the following cycles, which is normally the result of solid electrolyte interphase (SEI) film formation, the reduction of SnO x to metallic Sn, and partial irreversibility of lithium oxide. ,, In the subsequent cycles, the well-defined cathodic peaks at 0.27 and 0.56 V are related to lithium alloying with Sn. The distinct anodic peaks at 0.67, 0.75, and 0.82 V correspond to the delithiation process of Li x Sn. ,, The anodic peaks at 1.23 and 1.88 V are attributed to the partially reversible reaction of Sn to SnO 2 . , The entire process is described by eqs and . Near 2.95 V, an intense peak occurs in the CV curves of the first oxidation cycle, which might be on account of the side reactions between the electrolyte and the surface of the amorphous carbon .…”

“…24,43,44 The anodic peaks at 1.23 and 1.88 V are attributed to the partially reversible reaction of Sn to SnO 2 . 45,46 The entire process is described by eqs 2 and 3. Near 2.95 V, an intense peak occurs in the CV curves of the first oxidation cycle, which might be on account of the side reactions between the electrolyte and the surface of the amorphous carbon.…”

Incorporation of Cd-Doping in SnO2

“…Furthermore, stannic oxides present a good chemical stability with high melting and boiling points with low production costs. These can be applied as gas sensors, humidity sensors, and transparent electrodes for solar cells, varistors, optoelectronic devices, capacitors, flat-panel displays, high capacity anodes in lithium-ion batteries, and many other electronic device applications [1][2][3].…”