Solid-Liquid-Gas Management for Low-Cost Hydrogen Gas Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous nickel-hydrogen gas (Ni-H2) batteries offer excellent durability for grid-scale energy storage.
• High costs and limited performance of platinum electrodes hinder Ni-H2 battery adoption.
• Development of efficient, low-cost catalysts is crucial for advancing Ni-H2 battery technology.

Purpose of the Study:

• To report a low-cost nickel-molybdenum (NiMo) alloy as an efficient bifunctional catalyst for hydrogen evolution and oxidation reactions (HER/HOR).
• To improve the performance of Ni-H2 batteries using NiMo alloy catalysts in alkaline electrolytes.
• To demonstrate the potential of NiMo-based electrodes for practical grid-scale energy storage.

Main Methods:

• Synthesized a low-cost nickel-molybdenum (NiMo) alloy for HER/HOR catalysis.
• Characterized the catalytic activity of the NiMo alloy in alkaline electrolytes.
• Employed a solid-liquid-gas management strategy using multiwalled carbon nanotubes (MWCNT) to create a hydrophobic NiMo-MWCNT network.
• Fabricated and tested Ni-H2 battery cells with the developed NiMo-hydrophobic MWCNT electrodes.

Main Results:

• The NiMo alloy exhibited a high HOR mass-specific kinetic current (28.8 mA mg-1 at 50 mV) and a low HER overpotential (45 mV at 10 mA cm-2).
• The NiMo-hydrophobic MWCNT electrode demonstrated accelerated HER/HOR activities compared to conventional electrodes.
• Ni-H2 cells utilizing NiMo-hydrophobic MWCNT electrodes achieved a high energy density of 118 Wh kg-1.
• The developed Ni-H2 cells achieved a low cost of $67.5 kWh-1.

Conclusions:

• The NiMo alloy serves as an efficient, non-precious metal catalyst for Ni-H2 batteries.
• The hydrophobic NiMo-MWCNT electrode design enhances battery performance through improved charge transfer and gas management.
• Ni-H2 batteries based on this technology offer a compelling combination of high energy density, low cost, and excellent durability.
• These findings highlight the significant potential of NiMo-based Ni-H2 batteries for practical grid-scale energy storage solutions.