One-Step Synthesis of Mesoporous Chlorine-Doped Carbonated Cobalt Hydroxide Nanowires for High-Performance Supercapacitors Electrode

Facile synthesis of MnCo2S4 nanosheets as a binder-free electrode material for high performance supercapacitor applications

This paper reported an easy synthesis of MnCo2S4 (MCS) nanosheets by a one-pot solvothermal method for high performance supercapacitor electrode material applications. The obtained MCS nanosheets with an ultrathin thickness...

Nickel-Cobalt Hydroxides with Tunable Thin-Layer Nanosheets for High-Performance Supercapacitor Electrode

Layered double hydroxides as typical supercapacitor electrode materials can exhibit superior energy storage performance if their structures are well regulated. In this work, a simple one-step hydrothermal method is used to prepare diverse nickel-cobalt layered double hydroxides (NiCo-LDHs), in which the different contents of urea are used to regulate the different nanostructures of NiCo-LDHs. The results show that the decrease in urea content can effectively improve the dispersibility, adjust the thickness and optimize the internal pore structures of NiCo-LDHs, thereby enhancing their capacitance performance. When the content of urea is reduced from 0.03 to 0.0075 g under a fixed precursor materials mass ratio of nickel (0.06 g) to cobalt (0.02 g) of 3:1, the prepared sample NiCo-LDH-1 exhibits the thickness of 1.62 nm, and the clear thin-layer nanosheet structures and a large number of surface pores are formed, which is beneficial to the transmission of ions into the electrode material. After being prepared as a supercapacitor electrode, the NiCo-LDH-1 displays an ultra-high specific capacitance of 3982.5 F g^-1 under the current density of 1 A g^-1 and high capacitance retention above 93.6% after 1000 cycles of charging and discharging at a high current density of 10 A g^-1. The excellent electrochemical performance of NiCo-LDH-1 is proved by assembling two-electrode asymmetric supercapacitor with carbon spheres, displaying the specific capacitance of 95 F g^-1 at 1 A g^-1 with the capacitance retention of 78% over 1000 cycles. The current work offers a facile way to control the nanostructure of NiCo-LDHs, confirms the important affection of urea on enhancing capacitive performance for supercapacitor electrode and provides the high possibility for the development of high-performance supercapacitors.

Untying thioether bond structures enabled by "voltage-scissors" for stable room temperature sodium-sulfur batteries

A steady sulfur cathode is central to realizing stable room temperature sodium-sulfur (RT Na-S) batteries. Here, sulfur atoms are incorporated into carbon to form thioether bond functionalized carbon (SC) as a cathode material for sodium storage, which is capable of the complete elimination or great suppression of the shuttle effect of soluble poly-sulfides by the generation of insoluble sulfides in RT Na-S batteries using an ordinary carbonate electrolyte. This thioether bond structure (C-S-C) in sulfur-doped carbon can be disassembled by the assistance of "voltage-scissors" in the low voltage range of 0.01-0.50 V vs. Na/Na+. The small sulfur species derived from the thioether bond structure react with the sodium anode to form insoluble sulfides. Moreover, the insoluble sulfides Na2S2 and Na2S are confined in the carbon defects induced by the cleaved sulfur to prevent them from degrading the long-chain poly-sulfides. The distinctive electrochemical performance of SC enriches our understanding of the sulfur cathode, and could provide novel insights for constructing stable sulfur cathode materials for specific energy storage devices.