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14-billion-years-later noted: How Do Batteries Work? I had a request from an anon, so here goes. The first thing we need to know about batteries is that in essence what they’re doing is converting stored chemical energy into electrical energy. They do this by a series of reduction-oxidation reactions (redox). The first step involves the positively charged anode (anodes attract negatively charged ions called anions), at the anode electrons are moved from the electrolyte into the anode where they generate a voltage (which is a potential difference between energies at 2 points) and electromotive force. This is the oxidation step of the reaction. The electrolyte then converts into another compound or simply changes oxidation state. The electrons meanwhile go about their business and do whatever work they have to do before flowing into the cathode of the battery. At the cathode the corresponding reduction reaction occurs, quite separately to the oxidation component. Here electrons flow from the cathode into the second electrolyte which undergoes another chemical change. To complete the circuit some exchange of ions has to occur to make sure the flow continues, this is usually mediated by a salt bridge which connects the two electrolytes. Hope that helps!Image

14-billion-years-later noted:

How Do Batteries Work?

I had a request from an anon, so here goes. The first thing we need to know about batteries is that in essence what they’re doing is converting stored chemical energy into electrical energy. They do this by a series of reduction-oxidation reactions (redox). The first step involves the positively charged anode (anodes attract negatively charged ions called anions), at the anode electrons are moved from the electrolyte into the anode where they generate a voltage (which is a potential difference between energies at 2 points) and electromotive force. This is the oxidation step of the reaction. The electrolyte then converts into another compound or simply changes oxidation state. The electrons meanwhile go about their business and do whatever work they have to do before flowing into the cathode of the battery. At the cathode the corresponding reduction reaction occurs, quite separately to the oxidation component. Here electrons flow from the cathode into the second electrolyte which undergoes another chemical change. To complete the circuit some exchange of ions has to occur to make sure the flow continues, this is usually mediated by a salt bridge which connects the two electrolytes. Hope that helps!

Image

(via likeaphysicist)

Filed under physics chemistry