Lithium–sulfur batteries are deemed to have the opportunity to replace lithium‐ion batteries because of their high energy density. Nonetheless, the shuttling of soluble long‐chain polysulfides ...severely deteriorates the cyclic performances of the batteries. Herein, an encapsulated sulfur electrode to tackle the shuttle effect is designed. This high‐performance electrode is fabricated by encapsulating the active sulfur inside a sealing configuration composed of lithiated Nafion (Li‐Nafion), carbon black (BP2000), and a binder of polytetrafluoroethylene. The dense surface of the encapsulated configuration can physically obstruct the mobility of soluble polysulfides. Meanwhile, the sulfonic acid groups fixed on the Li‐Nafion backbone provide a robust electrostatic repulsion to inhibit the negatively charged polysulfides from migrating into the electrolyte. Therefore, the encapsulated sulfur electrode delivers 522.6 mAh g−1 at the 600th cycle with a retention of 80.36%, exhibiting a more competitive cyclic stability than the pristine sulfur electrode.
A Li‐Nafion‐supported sealing configuration is fabricated to encapsulate the pristine sulfur electrode to confine the polysulfides shuttle effectively. The dense surface of the configuration can physically obstruct the diffusion of soluble polysulfides. Meanwhile, the SO3− groups fixed on the Li‐Nafion backbone provide a robust electrostatic repulsion to prevent the negatively charged polysulfides from migrating into the electrolyte.
The room‐temperature (RT) Na/S battery is a promising energy storage system owing to suitable operating temperature, high theoretical energy density, and low cost. However, it has a poor cycle life ...and low reversible capacity. In this work, we report a long‐life RT‐Na/S battery with amorphous porous silica as a sulfur host. The sulfur is loaded into amorphous silica by a dipping method; the optimal sulfur loading is up to 73.48 wt %. Molecular dynamics simulation and first‐principles calculations suggest that the complex pores, acting as micro‐containers and the formation of Na‐O chemical bonds between amorphous silica and sodium polysulfide, give the electrodes a strong ability to inhibit sodium polysulfide shuttle. This would give rise to effectively avoiding the loss of active sulfur, corresponding to a superior capacity and an excellent cyclability even at 10 A gsulfur−1 (nearly 100 % coulomb efficiency and high reversible capacity of 955.8 mAh gsulfur−1 after 1460 cycles).
Sulfur as an electrode is loaded into amorphous silica by a facile dipping method. In charge/discharge process, the complex pores of amorphous silica, acting as micro‐containers and the formation of Na‐O chemical bonds between amorphous silica and sodium polysulfide, give the electrodes a strong ability to inhibit sodium polysulfide shuttle.
Hydrogen evolution reaction (HER) was studied on two types of amorphous Ni–P and one type of Ni–S electrode, all prepared by an electrodeposition. It was found that the activity of these electrodes ...depended considerably on the thickness of the electrode layer. Electrodes with thicker layers were more active than thinner ones. Also the absorption of both forms of hydrogen (i.e. underpotential absorbed hydrogen H
HU and overpotential absorbed hydrogen H
HO) depended considerably on the layer thickness. On the other hand, the relative amount of absorbed hydrogen related to the layer thickness did not depend on this thickness. It followed from the results that the main cause of the high activity for the HER was the internal stress in the layer. The stress originated during the electrodeposition of layers by codeposited hydrogen that absorbed in forming layers.
