Solid–Liquid–Gas Management for Low-Cost Hydrogen Gas Batteries
Taoli Jiang, Shuyang Wei, Linxiang Li, Kai Zheng, Xinhua Zheng, Sunhyeong Park, Shuang Liu, Zhengxin Zhu, Zaichun Liu, Yahan Meng, Qia Peng, Yuancheng Feng, Wei Chen
Abstract
Aqueous nickel-hydrogen gas (Ni-H 2 ) batteries with excellent durability (>10,000 cycles) are important candidates for grid-scale energy storage but are hampered by the high-cost Pt electrode with limited performance. Herein, we report a low-cost nickel-molybdenum (NiMo) alloy as an efficient bifunctional hydrogen evolution and oxidation reaction (HER/HOR) catalyst for Ni-H 2 batteries in alkaline electrolytes. The NiMo alloy demonstrates a high HOR mass-specific kinetic current of 28.8 mA mg –1 at 50 mV as well as a low HER overpotential of 45 mV at a current density of 10 mA cm –2, which is better than most nonprecious metal catalysts. Furthermore, we apply a solid–liquid–gas management strategy to constitute a conductive, hydrophobic network of NiMo using multiwalled carbon nanotubes (NiMo-hydrophobic MWCNT) in the electrode to accelerate HER/HOR activities for much improved Ni-H 2 battery performance. As a result, Ni-H 2 cells based on the NiMo-hydrophobic MWCNT electrode show a high energy density of 118 Wh kg –1 and a low cost of only 67.5 $ kWh –1 . With the low cost, high energy density, excellent durability, and improved energy efficiency, the Ni-H 2 cells show great potential for practical grid-scale energy storage.