Questions tagged [electrochemistry]

The branch of chemistry that deals with the study of redox reactions and how they can be applied to generate electricity (in electrochemical cells) and to carry out non-spontaneous reactions using electricity (electrolysis).

Electrochemistry is the scientific discipline studying the relationship between chemistry and electricity. It includes all technologies and techniques such as work on electrolysis, corrosion, batteries, fuel cells, accumulators, and electroplating.

In general, electrochemistry studies the relationship between chemical reactions and electricity. Electricity is the movement of electrons moving together in one direction. The chemical reaction that is happening in an electrochemical reaction will make electrons move from one side to another. These reactions are called oxidation-reduction reactions, meaning that electrons move between atoms. Some atoms are being oxidized, meaning that they lose an electron, and other atoms are being reduced, meaning that they gain an electron.

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What's the chemistry behind only charging a Lithium-ion battery to 80% capacity at most, to increase its lifespan?

What's the chemistry behind only charging a Lithium-ion battery to 80% capacity at most, to increase its lifespan? Over on the Skeptics StackExchange, a question has come up about charging Lithium-ion cells to just 80% of their maximum, in order to…
410 gone
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Deriving a reduction potential from two other reduction potentials

Given: \begin{align} \ce{Co^{3+}(aq) + e- &-> Co^{2+}(aq)} & E° &= \pu{+1.82 V} \\ \ce{Co^{2+}(aq) + 2e- &-> Co(s)} & E° &= \pu{-0.28 V} \end{align} what is the standard reduction potential for $\ce{Co^{3+}(aq) +3e- -> Co(s)}$? If I…
Anonymous Duck
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What happens inside salt bridges?

I don't understand how a salt bridge work exactly: what happens inside it and how it affect the cell's lifetime. I have already read: Salt Bridges/Porous Disks Salinic bridges in voltaic cells Difficulties understanding how salt bridge works What I…
standousset
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Bandgap of a semiconductor for photocatalytic water splitting

I'm reading a review article on photocatalytic water splitting (using semiconductors) and I came across the following: "To achieve photocatalytic water splitting using a single photocatalyst, the bandgap of the semiconductor must straddle the…
user34801
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Is greater relative AA battery capacity at high currents indicative of greater capacity at low currents?

I originally posted this on EE.SE but might be better here: Battery showdown compared the mAh and mWh capacity of different AA batteries discharged at 200mA. Would the relative capacities of each battery type (within the same chemistry type) be the…
geometrikal
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Why can't a galvanic cell be a single cell?

I get that galvanic cells require a salt bridge to maintain neutrality so the cathode doesn't become saturated with electrons, but why is a two-cell setup required? Wouldn't the spontaneous reaction occur and neutral conditions be met if Cu and Zn…
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How to separate a 5 atom thick layer of Cu from Au

I've become very curious about (electrochemical) atomic layer deposition (ALD) via surface limited redox replacement. Since the technique allows for deposition of metals in atom thick layers it's possible to create films of nearly exact atomic…
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Can I use one alkaline battery to recharge another?

Unfortunately, I don't have batteries to waste to test this myself, but I am curious... Let's say you have two identical batteries. AA Duracell. Now let's say you run one of the batteries through an LED until the LED starts emitting at half the…
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Why does a complete discharge destroy a Li-Ion-Battery?

I read that completely discharging a Lithium Ion Battery is a very bad idea because it will lose plenty of capacity. But why? I know that the reaction (fot the LiFePO4 battery) is: $$ \ce{LiFePO4 + C6 <=>[1 e-] FePO4 + LiC6 } $$ So at a complete…
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How does a reference electrode work in a three electrode system?

This is what I understand about three electrode electrochemistry (correct me if I am wrong): The working electrode is where the reaction of interest happens, e.g. copper ions reduced to solid copper. The auxiliary/counter electrode supplies the…
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Is this product description wrong and a simple battery and not a fuel cell?

I won this "toy" at a science fair... Now I have to make a short presentation about it in school. On the package description they describe its energy source as "fuel cell"... It consists out of a metal plate(magnesium), a black metal plate with a…
leAthlon
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Why the water in an lead-acid battery isn't self-electrolysed (at any significant rate)?

I'm reading Detchko Pavlov's Lead-Acid Batteries: Science and Technology (maybe an old version than the link) and in the first chapter the book mentioned "it is currently unknown why electrolysis of water happens so slowly". If we think about it,…
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Can lead-acid batteries release CO? Or can a CO sensor detect gasses other than CO?

I recently found myself troubleshooting a CO alarm on a houseboat. Inside the cabin, a Fluke CO-220 was reading 40 ppm. In the generator engine compartment, the CO level was zero (while the generator was running). We eventually found the source of…
Jonathon Reinhart
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galvanic corrosion in the wild: where is the reduction?

Galvanic corrosion occurs of an active metal (i.e. iron or zinc) in contact with a passive metal (i.e. copper) in a conductive solution. A famous example is the corrosion of iron girders in contact with copper in the statue of liberty. Although the…
Kevin Kostlan
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Still taught to reverse oxidation half cells in electrochemistry?

In a question, Oxidation of metals/halogens by oxygen gas in acidic aqueous solution, there was a point made that reduction half-cells should not be reversed. I was taught ($\approx 1970$) in the following manner. Given the reduction half…
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