Russian chemists have developed a neutralization battery that generates electricity from the difference in pH between two liquids, for example, waste acids and alkalis from chemical plants. The results of the research are published in the journal ChemSusChem.
Every year more and more electricity is produced in the world and people need more and more energy storage devices. They come in many different types, from conventional lithium-ion batteries and lead-acid batteries to hydrogen fuel cells and many others. Each technology has its own pros and cons: some drives are almost never discharged in idle mode and therefore are suitable for long-term storage of electricity, others can produce very high currents, and still others can store a record amount of energy per unit of their mass, which makes them irreplaceable, for example, for submarines.
Among the energy storage devices, there are especially exotic ones. So, in the 70s of the XX century, scientists proposed the concept of a neutralization battery, in which energy is obtained due to the difference in the pH values of two liquids called electrolytes. In fact, it is a fuel that is converted into electricity. Neutralizing batteries have rather low characteristics: they do not provide high power during discharge and cannot store large amounts of energy, but they have an important advantage – the cost of electrolytes. Lithium-ion batteries require relatively expensive lithium salts, hydrogen fuel cells require hydrogen, and neutralization batteries can use almost any liquid
The principle of operation of a neutralization battery is based on the fact that two liquids with excellent pH are pumped through different capacities inside the battery. They do not physically mix with each other, but they enter into electrochemical reactions, the products of which pass from one container to another. Due to this kind of circulation of substances, energy is released or, conversely, stored.
Russian scientists have worked out the design of a neutralization battery based on dilute solutions of HCl and NaOH. The key idea was to use hydrogen electrodes. As a result, reactions with the participation of hydrogen take place in both containers, and the total neutralization energy is made up of them. At the same time, even sea water and waste from chemical plants are suitable for the operation of the neutralization battery. The design itself was developed by scientists from the Mendeleev University of Chemical Technology, IPCP RAS and IPCE RAS.
“The key idea is the use of hydrogen electrodes. The reactions are spaced apart and take place in two containers with the participation of hydrogen, and the total energy of chemical neutralization gives electrons, that is, we get electricity from practically nothing. At first it seems that this is some kind of trick, but this is a real technology, ”says Pavel Loktionov, the first author of the study.
The authors have already proved the principal possibility of recharging such a device, and its specific power was 6 mW / cm² – this is one of the highest indicators among neutralization batteries.