SeC Bonding Promoting Fast and Durable Na⁺ Storage in Yolk–Shell SnSe₂@SeC

Abstract

Tin‐based compounds have received much attention as anode materials for lithium/sodium ion batteries owing to their high theoretical capacity. However, the huge volume change usually leads to the pulverization of electrode, giving rise to a poor cycle performance, which have severely hampered their practical application. Herein, highly durable yolk–shell SnSe2 nanospheres (SnSe2@SeC) are prepared by a multistep templating method, with an in situ gas‐phase selenization of the SnO2@C hollow nanospheres. During this process, Se can be doped into the carbon shell with a tunable amount and form SeC bonds. Density functional theory calculation results reveal that the SeC bonding can enhance the charge transfer properties as well as the binding interaction between the SnSe2 core and the carbon shell, favoring an improved rate performance and a superior cyclability. As expected, the sample delivers reversible capacities of 441 and 406 mAh g−1 after 2000 cycles at 2 and 5 A g−1, respectively, as the anode material for a sodium‐ion battery. Such performances are significantly better than the control sample without the SeC bonding and also other metal selenide‐based anodes, evidently showing the advantage of Se doping in the carbon shell.

Highly Efficient Na+ Storage in Uniform Thorn Ball-Like α-MnSe/C Nanospheres

“…3c). The sample displayed a significant capacity loss in the first cycle and then a gradual recovery in the specific capacity, which has been reported in many studies about batteries and supercapacitors [48,57]. This phenomenon is quite noticeable in metal selenides such as FeSe, FeSe 2 and CoSe 2 [58][59][60], and it could be attributed to the electrochemical activation of active materials and a possible formation of a polymeric gel-like layer that provides additional capacity through "pseudo-capacitance" [59].…”

“…It can be observed that the major weight loss takes place between 330 °C and 600 °C. It has been discussed [32,47,48] that between 350 and 450 °C, the sample has reached the sublimation temperature of selenium dioxide, and the decrease in quality can be explained by the volatilization of SeO 2 . In the subsequent 450-550 °C window, the weight loss could be attributed to the combustion of carbon [49].…”

“…Through calculation, the b values of all the current peaks are greater than 0.5, indicating that the storage process is based on the capacitive behaviors combined with ion diffusion. Furthermore, the detailed contribution for each behavior can be deconvolved and calculated using equation [32,48,68]:…”

Generating Short‐Chain Sulfur Suitable for Efficient Sodium–Sulfur Batteries via Atomic Copper Sites on a N,O‐Codoped Carbon Composite

“…Sodium-sulfur (Na-S) batteries are considered as a promising alternative for widely studied Li-ion batteries, owing to their high theoretical energy densities and natural abundance of both sulfur and sodium sources. [1][2][3][4][5][6][7][8] However, conventional Na-S batteries are normally operated beyond 300 °C and rely on molten electrodes, which is costly and raises some safety concerns, thus inhibiting their large-scale application. [9][10][11][12][13] Thus, room temperature Na-S batteries relying on liquid electrolytes have attracted a lot of attention as low-cost energy storage alternative.…”

3D Carbon Networks: Design and Applications in Sodium Ion Batteries

“…To date, numerous kinds of materials have been proposed for SIBs electrodes. For anodes, it contains carbon‐based materials, [10a] metal compound materials (such as metal oxides, [1c] metal sulfides, [10b] metal selenides [10c] and metal phosphides [10d] ), and alloy materials, [13] etc., while cathodes are usually composed by polyanionic compounds, [14] transition‐metal oxides, [15] and organic compounds [16] . Among the aforementioned materials, extensive study on carbon has been carried out from the earliest stage.…”