Ultrafine Mix-Phase SnO-SnO₂ Nanoparticles Anchored on Reduced Graphene Oxide Boost Reversible Li-Ion Storage Capacity beyond Theoretical Limit

Abstract

Tin-based materials with high specific capacity have been studied as high-performance anodes for Li-ion storage devices. Herein, a mix-phase structure of SnO-SnO2@rGO (rGO = reduced graphene oxide) was designed and prepared via a simple chemical method, which leads to the growth of tiny nanoparticles of a mixture of two different tin oxide phases on the crumbled graphene nanosheets. The three-dimensional structure of graphene forms the conductive framework. The as-prepared mix phase SnO-SnO2@rGO exhibits a large Brunauer-Emmett-Teller surface area of 255 m2 g–1 and an excellent ionic diffusion rate. When the resulting mix-phase material was examined for Li-ion battery anode application, the SnO-SnO2@rGO was noted to deliver an ultrahigh reversible capacity of 2604 mA h g–1 at a current density of 0.1 A g–1. It also exhibited superior rate capabilities and more than 82% retention of capacity after 150 charge–discharge cycles at 0.1 A g–1, lasting until 500 cycles at 1 A g–1 with very good retention of the initial capacity. Owing to the uniform defects on the rGO matrix, the formation of LiOH upon lithiation has been suggested to be the primary cause of this very high reversible capacity, which is beyond the theoretical limit. A Li-ion full cell was assembled using LiNi0.5Mn0.3Co0.2O2 (NMC-532) as a high-capacity cathodic counterpart, which showed a very high reversible capacity of 570 mA h g–1 (based on the anode weight) at an applied current density of 0.1 A g–1 with more than 50% retention of capacity after 100 cycles. This work offers a favorable design of electrode material, namely, mix-phase tin oxide-nanocarbon matrix, exhibiting adequate electrochemical performance for Li storage applications.

Boosting Photocatalytic Hydrogen Evolution Activity by Accelerating Water Dissociation over Rh/Zn(OH)2 Catalyst in Alkaline Solution

“…On the other hand, the Zn­(OH) 2 catalyst system displays two-exponential fluorescence decay kinetics with an average lifetime of 1.59 ns. This decay comprises a long-lived component at 1.861 ns, likely associated with EY molecules interacting with Zn­(OH) 2 , and a short-lived component at 1.351 ns, corresponding to monomeric EY molecules . This result indicates that the Zn­(OH) 2 can rapidly transfer the electron of excited EY due to its 3D network structure, which can efficiently adsorb the EY molecules.…”

“…This decay comprises a long-lived component at 1.861 ns, likely associated with EY molecules interacting with Zn(OH) 2 , and a short-lived component at 1.351 ns, corresponding to monomeric EY molecules. 51 This result indicates that the Zn(OH) 2 can rapidly transfer the electron of excited EY due to its 3D network structure, which can efficiently adsorb the EY molecules. However, the average lifetime is further prolonged for the Rh/Zn(OH) 2 catalyst system, and the average value of 1.76 ns is achieved, suggesting that the strong interaction in Rh/Zn(OH) 2 significantly enhances the acceleration of the photogenerated electron The intermittent photocurrent responses for the Zn(OH) 2 , Rh, and Rh/Zn(OH) 2 catalysts were measured on the ITO electrode to study the photogenerated electron transfer mechanism.…”

Elucidating the oxygen reduction reaction kinetics on defect engineered nanocarbon electrocatalyst: interplay between the N-dopant and defect sites

“…S5. † 69 The successful removal of N atoms from the carbon skeleton by annealing was veried by the comparison of deconvoluted N 1s spectra of DG 1:1 -T that depict the characteristic peaks for pyridinic N (398.0 eV), pyrrolic N (399.9 eV), graphitic N (401.0 eV) and oxidized N (403.5 eV), as shown in Fig. 4c.…”

First-Principles Calculations to Investigate Coupling Fe Doping with Oxygen Vacancies in Stannic Oxide and Their Physical Properties

“…Stannic oxides (SnO 2 ) have gained a lot of attention in the fields of catalysis, such as thin-film transistors, gas sensors, lithium-ion batteries, humidity sensors, target drug delivery, and dye-sensitized solar cell applications due to their wide band gap, electron mobility, and excellent optical and chemical stability. − SnO 2 has several advantages, including affordability, safety against chemicals, long-term stability against rust, high surface-to-volume ratio, and being eco-friendly. China produced 27% of the 31,000 tons of tin in the world in 2019, according to the US Geological Survey (USGS).…”