RESEARCHERS at MIT claim liquid batteries could be useful as a long-life and low-cost solution for smoothing out the erratic power supplies of renewable energy sources.
The system uses high-temperature batteries whose liquid components naturally settle into distinct layers because of their different densities.
The three molten materials form the positive and negative poles of the battery, as well as a layer of electrolyte in between. All three layers are composed of materials that are abundant and inexpensive.
Donald Sadoway, the John F. Elliott Professor of Materials Chemistry at MIT and the senior author of the new paper, said the team explored many chemistries in order to find the right combination of electrical properties, density differences and availability.
One combination they found was to use magnesium for the negative electrode (top layer), a salt mixture containing magnesium chloride for the electrolyte (middle layer) and antimony for the positive electrode (bottom layer). The system would operate at a temperature of 700 degrees Celsius.
In this formulation, Sadoway explains, the battery delivers current as magnesium atoms lose two electrons, becoming magnesium ions that migrate through the electrolyte to the other electrode. There, they reacquire two electrons and revert to ordinary magnesium atoms, which form an alloy with the antimony.
To recharge, the battery is connected to a source of electricity, which drives magnesium out of the alloy and across the electrolyte, where it then rejoins the negative electrode.
The team has scaled up their experiments over the years, and now are working on a version which has 200 times the power storage capacity of the initial version.
The team is continuing to work on optimizing all aspects of the system, including the containers used to hold the molten materials and the ways of insulating and heating them, as well as ways of reducing the operating temperature to help cut energy costs.
Liquid batteries to smooth road for renewable energy
TAG:power supplies environmental electronics solar power
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