Prototype of Ni-MH battery based on metal hydride negative electrodes withmetal-carbon composites

摘要

Nickel-metal hydride rechargeable batteries are thenext generation of nickel-based secondary batteries. The toxic cadmium used in negative electrodes innickel-cadmium batteries was replaced by hydrogen storage alloys. Thecapacity and power of Ni-MH batteries aretwice (or more) ashigh as those of Ni-Cd batteries of equivalent size. A hydrogen absorbing alloy needs to meet the specific requirements as: high real capacity of the alloy in the absorption/desorption process, proper changes of the lattice parameters during the hydrogen absorption, stability in concentrated alkalis, good kinetics of electrode reactions, fast activation of the alloy and reasonable price of the active mass. To achieve the above-mentioned ends, the battery properties can be improved by carbon- based structures usedas additives. Thecomposite active mass in a negative electrode contributes to a decrease in the internal resistance, enhances the kinetics and reduces the overall battery costs.