High‐Performance Sodium‐Ion Batteries and Sodium‐Ion Pseudocapacitors Based on MoS₂/Graphene Composites

Abstract

Dou, S. (2014). High-performance sodium-ion batteries and sodium-ion pseudocapacitors based on MoS2/graphene composites. Chemistry: A European Journal, 20 (31), 9607-9612.High-performance sodium-ion batteries and sodium-ion pseudocapacitors based on MoS2/graphene composites Abstract Sodium-ion energy storage, including sodium-ion batteries (NIBs) and electrochemical capacitive storage (NICs), is considered as a promising alternative to lithium-ion energy storage. It is an intriguing prospect, especially for large-scale applications, owing to its low cost and abundance. MoS2 sodiation/desodiation with Na ions is based on the conversion reaction, which is not only able to deliver higher capacity than the intercalation reaction, but can also be applied in capacitive storage owing to its typically sloping charge/ discharge curves. Here, NIBs and NICs based on a graphene composite (MoS2/G) were constructed. The enlarged d-spacing, a contribution of the graphene matrix, and the unique properties of the MoS2/G substantially optimize Na storage behavior, by accommodating large volume changes and facilitating fast ion diffusion. MoS2/G exhibits a stable capacity of approximately 350 mAh g−1 over 200 cycles at 0.25 C in half cells, and delivers a capacitance of 50 F g−1 over 2000 cycles at 1.5 C in pseudocapacitors with a wide voltage window of 0.1-2.5 V.

Conversion and displacement reaction types of transition metal compounds for sodium ion battery

“…Although the discharge capacity decays drastically in the first 5 cycles, it stabilizes at around 70 mAhg À1 since the 6th cycle and the discharge capacity of the thin film electrode for the 200 th cycle is 55 mAhg À1 . Recently, the graphene could benefits for the outstanding cycling performance of nanocomposites based graphene [24,25] for sodium-ion battery, the further cycling performance improvement of FeSe and CuWO 4 may be made by using their composites based graphene as electrodes. Fig.…”

Nanoengineering to Achieve High Sodium Storage: A Case Study of Carbon Coated Hierarchical Nanoporous TiO2 Microfibers

“…The newly formed cubic phase can exhibit self‐improving capacity via self‐organization based on the electrochemical reactions between TiO 2 and sodium ions 23. The solid TiO 2 microfibers (STMF) undergo slow self‐organization over 100 cycles due to their good crystallization, which leads to a slight capacity increase from 41 to 60 mA h g −1 .…”

MoS2 with an intercalation reaction as a long-life anode material for lithium ion batteries

“…14 Then with continuous Li + intercalation, the structure of the layered MoS 2 decomposes to Mo metal and Li 2 S. This step possesses large volume expansion (∼103%) leading to electrode pulverization. [15][16][17] Because the charge products can never return back to MoS 2 again, the reaction mechanism of the following cycles is the reversible reaction between Li 2 S and S, just the same as that for Li/S batteries. This presents the problem that MoS 2 should also come across the difficulties encountered in Li/S batteries, such as the severe capacity loss owing to the active material dissolution, the polysulfide shuttling effect, and the side reaction between polysulfides and the electrolyte.…”