Multilayered Architecture Assembled from Sn(HPO₄)₂ Nanosheets and Reduced Graphene Oxide As Superior Cyclability Anodes for Sodium-Ion Batteries

Abstract

The two-dimensional layered material of Sn(HPO4)2 nanosheets (SNSs) with a controllable nanosheet structure and a large interlayer distance is expected to be a potential anode material for sodium ion storage. However, poor conductivity and easy agglomeration are daunting challenges to realize the practical application of the SNS as an anode material. To overcome these difficulties, a two-dimensional multilayered architecture composed of SNSs and reduced graphene oxide (rGO) is assembled by utilizing the electrostatic repulsion between the SNS and graphene oxide and by an assisting liquid nitrogen rapid freezing method. Mainly owing to the solid solution reaction mechanism of SNSs, the excellent conductivity and interfacial charge storage of rGO, and their interaction with each other, the rGO/SNS anode exhibits improved rate capability, outstanding cycling stability of 78.6% capacity retention after 10,000 cycles at 5 A g–1, and high pseudocapacitance of a 66% capacitive contribution ratio at 0.5 mV s–1. This work is expected to promote the development of SNS-based nanomaterials for electrochemical energy storage.

Slope-Dominated N/S Co-Doped Carbon Anode Derived from Pitch for Sodium-ion Batteries

“…This disparity in capacitance contribution between NSPC6-700 and undoped PC could primarily be attributed to the variance in defect concentration, where undoped PC’s relatively lower defect concentration limits the availability of active sites for sodium ion adsorption on its surface. Effective control of capacitance during sodium storage has the potential to significantly enhance the material’s overall performance, likely attributed to the high density of defects on the material’s surface and its rapid reaction kinetics …”

“…Effective control of capacitance during sodium storage has the potential to significantly enhance the material's overall performance, likely attributed to the high density of defects on the material's surface and its rapid reaction kinetics. 38 The diffusion coefficient of sodium ions in NSPC6-700 was determined by analyzing the galvanostatic intermittent titration technique (GITT) curve. 36,39 In Figure 5d, a pulse current of 30 mAh g −1 was observed for 0.5 h with rest intervals of 2 h. The resulting sodium ion diffusion coefficients (D values) as a function of voltage are presented in Figure 5e and f.…”

Multilayered SnP2O7/Reduced Graphene Oxide Architecture with High-Rate Lithium- and Sodium-Ion Storage

“…Graphene oxide (GO) (10 mg) obtained by a modified Hummer’s method was dispersed into 50 mL of H 2 O under stirring and ultrasound, and then, the GO aqueous dispersion was crushed in a 900 W ultrasonic cell crusher disruptor (JY92-IIDN, SCIENTZ) for 0.5 h. The above GO dispersion was then mixed with 100 mL of 1 mg mL –1 Sn­(HPO 4 ) 2 nanosheets prepared by liquid-phase exfoliation . The mixture was rapidly frozen by adding liquid nitrogen, and the Sn­(HPO 4 ) 2 /GO was prepared after freeze-drying for 48 h. Finally, the Sn­(HPO 4 ) 2 /GO was annealed in an Ar atmosphere at 800 °C for 4 h to obtain the SnP 2 O 7 /rGO composite.…”