Flexible SnTe/carbon nanofiber membrane as a free-standing anode for high-performance lithium-ion and sodium-ion batteries

Flexible electrode plays a key role in flexible energy storage devices. The SnTe/C nanofibers membrane (SnTe/CNFM) with excellent mechanical flexibility has been successfully synthesized for the first time through electrospinning, and it demonstrates outstanding electrochemical performance as free-standing anode for lithium/sodium-ion batteries. The SnTe/CNFM electrode delivers a discharge capacity of 526.7 mAh g^-1 at 1000 mA g^-1 after 1000 cycles in lithium-ion half-cells and a discharge capacity of 236.5 mAh g^-1 at 500 mA g^-1 after 80 cycles in lithium-ion full-cells with a LiFePO₄ cathode. Not only that, it shows a discharge capacity of 182.7 mAh g^-1 at 200 mA g^-1 after 200 cycles in sodium-ion half-cells and a high discharge capacity of 207.0 mAh g^-1 at 500 mA g^-1 after 50 cycles in sodium-ion full-cells with a Na_0.44MnO₂ cathode. Moreover, the prepared SnTe/CNFM exhibits good mechanical flexibility. The SnTe/CNFM can still return to its original state without any breakage after bending, curling, folding and kneading. These results indicate that SnTe/CNFM is expected to become one of the promising free-standing anodes for lithium/sodium-ion batteries.

Flowerlike Tin Diselenide Hexagonal Nanosheets for High-Performance Lithium-Ion Batteries

SnSe2 nanosheet is a common anode for lithium-ion batteries (LIBs), but its severe agglomeration hinders its practical application. Herein, a three-dimensional (3D) SnSe2 nanoflower (F-SnSe2) composed of non-stacking vertical upward hexagonal nanosheets was prepared through a colloidal method as an anode material for LIBs. Benefiting from the advantages of fast reaction-diffusion kinetics and buffering unavoidable volume variation during cycling, the F-SnSe2 electrode displays remarkable specific capacity of 795 mAh g-1 after 100 cycles at 100 mA g-1 and superior rate performance (282 mAh g-1 at 2,000 mA g-1). This work provides an effective way to get non-stacking nanosheets in energy storage field.

Core-shell (nano-SnX/nano-Li4Ti5O12)@C spheres (X = Se,Te) with high volumetric capacity and excellent cycle stability for lithium-ion batteries

Among binary tin chalcogenides as anode materials for lithium-ion batteries, SnSe and SnTe have attracted attention due to their high theoretical volumetric capacity. However, they suffer from sluggish dynamics and serious agglomeration during lithiation/delithiation processes, which leads to inferior cycling performance. This study reports core-shell structure (nano-SnSe/nano-Li₄Ti₅O₁₂)@C and (nano-SnTe/nano-Li₄Ti₅O₁₂)@C [denoted as (n-SnX/n-LTO)@C] with extraordinary lithium storage stability. Benefiting from the well-designed structural merits, the core-shell structure of (n-SnX/n-LTO)@C is well preserved over 500 cycles, suggesting its high structural integrity. The (n-SnSe/n-LTO)@C and (n-SnTe/n-LTO)@C anodes deliver high initial volumetric capacities of 3470.1 and 3885.4 mA h cm^-3 at 0.2 A g^-1 and maintain capacities of 2066.0 and 1975.3 mA h cm^-3 even after 500 cycles, respectively. This work provides a new avenue for designing novel binary tin chalcogenide lithium-ion battery anodes with high volumetric capacity and superior long-term cycling performance.

Surface modification of Li-rich manganese-based cathode materials by chemical etching

Chemical etching modifies the surface composition of a Li-rich Mn-based cathode and generates a thin amorphous layer that stabilizes the structure.