A Flexible Film with SnS₂ Nanoparticles Chemically Anchored on 3D‐Graphene Framework for High Areal Density and High Rate Sodium Storage

Abstract

The design and construction of flexible electrodes that can function at high rates and high areal capacities are essential regarding the practical application of flexible for sodium ion batteries (SIBs) and other energy storage devices, which remains significantly challenging by far. Herein, we report a flexible and three-dimensionally porous graphene nanosheets/SnS 2 (3D-GNS/SnS 2 ) film as highperformance SIB electrode. In this hybrid film, the GNS/SnS 2 microblocks serve as pillars to assemble into a 3D porous and interconnected framework, enabling fast electron/ion transport; while the GNS bridges the GNS/SnS 2 microblocks into a flexible framework to provide satisfactorily mechanical strength and long-range conductivity. Moreover, the SnS 2 nanocrystals, which chemically bond with GNS, provide sufficient active sites for Na-storage and ensure the cycling stability. Consequently, this flexible 3D-GNS/SnS 2 film exhibits excellent Na-storage performances, especially in terms of high areal capacity (2.45 mAh cm -2 ) and high rates with superior stability (385 mAh g -1 at 1.0 A g -1 over 1000 cycles with ~100% retention). A flexible SIB full cell using this anode exhibits high and stable performance under various bending situations. Thus, this work would provide a feasible route to prepare flexible electrodes with high practical viability for not only SIBs but also other energy storage devices.

Encapsulating Sulfides into Tridymite/Carbon Reactors Enables Stable Sodium Ion Conversion/Alloying Anode with High Initial Coulombic Efficiency Over 89%

“…To highlight their superiorities on Na storage, other state‐of‐the‐art sulfide‐based SIB anodes reported in previous literatures are summarized in Table 1 . Among them, [ 19–23,31–37 ] our anodes with a high mass loading ratio demonstrate notable merits including stable cyclic endurance, superior rate capability, and extraordinary ICE than other counterparts. This may be principally attributed to their unique properties for Na storage, as endowed by conformal/ robust nanoarmors tightly surrounding inside SnS 2 units (See a schematic in Figure 4i).…”

“…31–1327). [ 20–23,31–36 ] In next charge stage (0.005–1.3 V), Na 15 Sn 4 peaks diminish or eventually disappear due to dealloying reactions. When charged to 1.7 V (or even higher to 3 V), only a flat/broad diffraction signal is observed, illustrating the evolution of Sn into SnS 2 at a low crystallinity.…”

“…Their chemical composition at distinct charge/discharge stages is further reflected by X‐ray photoelectron spectroscopy (XPS). [ 19–23,31–36 ] In total charge/discharge procedures (Figure 5c), Sn 3d spectra exhibit two strong peaks for Sn 3d 5/2 and Sn 3d 3/2 photoelectron emissions at binding energy (BE) values of 486.7 and 495.2 eV, respectively, corresponding to the Sn 4+ chemical valence state. After being discharged to 0.005 V, peaks are shifted by ≈0.4 eV to lower BEs that correspond to Sn 3d 5/2 and Sn 3d 3/2 of Sn 2+ , solidly verifying the reduction of SnS 2 .…”

“…The synthesis of protective t‐ SiO 2 layers can be achieved via facile Stöber and chemical vapor deposition (CVD) methods, using TEOS as Si resources. [ 33 ] 0.1 g SnO 2 nanospheres were dispersed into a mixture containing 80 mL ethanol, 20 mL deionized water and 15 mL ammonium hydroxide by magnetic stirring over 10 min. Later, 150 µL TEOS (≈99%) liquid was dropwise added to form a mixture, which was then stirring at 85 °C for 6 h and filtered to collect SnO 2 @ n Si(OH) 4 intermediates.…”

Recent Advances in Emerging Non‐Lithium Metal–Sulfur Batteries: A Review

“…[14][15][16] As mentioned above, the anticipation of the increasing price and limited availability of Li has become a strong driving force for the exploration of other alkali and alkaline earth metals. [4,17,18] Non-lithium metal−sulfur batteries (MSBs) fabricated by coupling naturally abundant and environmentally friendly sulfur cathode with other metal anodes have attracted extensive interest, because of the similar electrochemical conversion reactions. [19] For example, sodium (Na) and potassium (K) have been employed because they locate the same group right below Li in the periodic table, thus sharing similar physical and chemical properties.…”