Unique Double-Interstitialcy Mechanism and Interfacial Storage Mechanism in the Graphene/Metal Oxide as the Anode for Sodium-Ion Batteries

Abstract

Graphene/metal oxides (G/MO) composite materials have attracted much attention as the anode of sodium ion batteries (SIBs), because of the high theoretical capacity. However, most metal oxides operate based on the conversion mechanism and the alloying mechanism has changed to Na 2 O after the first cycle. The influence of G/Na 2 O (G/N) on the subsequent sodiation process has never been clearly elucidated. In this work, we report a systematic investigation on the G/N interface from both aspects of theoretical simulation and experiment characterization. By applied first-principles simulations, we find that the sluggish kinetics in the G/MO materials is mainly caused by the high diffusion barrier (0.51 eV) inside the Na 2 O bulk, while the G/N interface shows a much faster transport kinetics (0.25 eV) via unique double-interstitialcy mechanism. G/ N interface possesses an interfacial storage of Na atom through the charge separation mechanism. The experimental evidence confirms that high interfacial ratio structure of G/N greatly improves the rate performance and endows G/MO materials the interfacial storage. Furthermore, the experimental investigation finds that the high interfacial ratio structure of G/N also benefits from the reversible reaction between SnO 2 and Sn during cycling. Lastly, the effects of (N, O, S) doping in graphene systems at the G/N interface were also explored. This work provides a fundamental comprehension on the G/MO interface structure during the sodiation process, which is helpful to design energy storage materials with high rate performance and large capacity.

Electrode Materials for High-Performance Sodium-Ion Batteries

“…Furthermore, another concern when it comes to metal oxide anodes are the volume changes that occur during sodium insertion and extraction, which may lead to an agglomeration of metal oxide particles and even cracks or the pulverization of the active material causing loss of contact and an impedance increase in the cell [129,130]. Those facts combined may affect the cell performance, causing capacity and rate capability to decrease [131,132]. Regarding the future perspectives of metal oxide anodes, aiming to provide capacities closer to the theoretical capacity values for metal oxides, strategies using carbon materials and nanostructuring is expected to increase the mobility of Na + ions in these anodes, as well as the ability to accommodate volume expansion.…”

Sulfur-Deficient Porous SnS2−x Microflowers as Superior Anode for Alkaline Ion Batteries

“…As a typical layered metal dichalcogenide material, SnS 2 is a typical two-dimensional layered structure and the large interlayer spacing could not only store the intercalated Li + or Na + ions but also release the stress induced by volume change [13]. However, as a ceramic semiconductor, tin disulfide suffers from low electronic conductivities [14][15][16][17][18][19]. Different highly conductive materials have been added to composite with SnS 2 , such as grapheme [20][21][22][23][24][25], PPy [18], and so on [26,27].…”

Turning waste makeup cotton to a hollow structured carbon as anode for high‐performance lithium ions batteries

“…By contrast, electrochemical energy storage (EES) is regarded as a high‐efficient storage way for clean energy [3]. Among numerous EES devices, lithium‐ion batteries (LIBs) have attracted widespread attention in recent years due to their high energy density, long cycling life and friendly eco‐environment [4, 5], which have been widely used in portable electronic devices, hybrid electric vehicles, smart power grids and so forth [6, 7].…”