High temperature sodium batteries with inorganic electrolytes are attracting increasing attention due to their high thermal stability, reliability, long-cycle life and safety. Despite the intensive investigation of Na-NiCl 2 batteries during last decades, designing a stable conducting network in the cathode is still challenging but desirable. In this work, a new cathode structure composed of Ni nanowires with an effective electron conducting network is proposed for planar sodium–nickel chloride batteries . During the first stage of charge, Ni nanowires reacted with Cl ion to form NiCl 2 on the surface and the excessive Ni nanowires inside can serve as conducting framework to facilitate the fast electron transport . As expected, the metal nanowires show a high specific capacity of 130 mA h g −1 (∼14 mAh cm −2 ) at 0.05 C after 100 cycles. Meanwhile, the batteries show stable cycling performance at 0.05 C with a high cut-off energy density of 360 W h kg −1 , much higher than the traditional tubular sodium-nickel chloride batteries (∼100 Wh kg −1 ). Scanning electron microscope (SEM) images of the cathode after long cycling reveal the ultra-slow growth of Ni particles, confirming the excellent stability of the prepared nanowires cathode.
Yang Hongchao,Wang Changhong,Hu Feng,Zhang Yejun,Lu Huan,Wang Qiangbin
The synthesis of atomic-scale metal catalysts is a promising but very challenging project. In this work, we successfully fabricated a hybrid catalyst of Ptc/Ni(OH) 2 with atomic-scale Pt clusters uniformly decorated on porous Ni(OH) 2 nanowires (NWs) via a facile room-temperature synthesis strategy. The as-obtained Pt c /Ni(OH) 2 catalyst exhibits highly efficient hydrogen evolution reaction (HER) performance under basic conditions. In 0.1 mol L −1 KOH, the Pt c /Ni(OH) 2 has an onset overpotential of ~0 mV vs. RHE, and a significantly low overpotential of 32 mV at a current density of 10 mA cm −2 , lower than that of the commercial 20% Pt/C (58 mV). The mass current density data illustrated that the Pt c /Ni(OH) 2 reached a high current density of 6.34 Amg
−1 Pt
at an overpotential of 50 mV, which was approximately 28 times higher than that of the commercial Pt/C (0.223 A mg
−1 Pt
) at the same overpotential, proving the high-efficiency electrocatalytic activity of the as-obtained Pt c /Ni(OH) 2 for HER under alkaline conditions.