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High voltage batteries, not 2V per cell

  1. Mar 16, 2007 #1
    Most batteries have a low voltage output like a lead acid +- 2.2V per cell
    And carbon + zinc have something like 1.5V and so it goes on.

    Can a battery have a high output voltage without putting it in series

    Example:

    I want a battery with 100V DC output per cell, does that exist or not, and if not, how can that be done?
     
  2. jcsd
  3. Mar 16, 2007 #2

    mrjeffy321

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    100 Volts per cell….no, I don’t think so.

    You are limited by the standard reduction potential difference between the substance in your battery being reduced and the substance being oxidized.

    For “standard” values (with 1 Molar solutions),
    E _cell = E_oxidiation + E_reduction

    So, for example, if you had a Copper-Zinc battery,
    The Zinc would be getting oxidized at the anode,
    Zn --> Zn+2 + 2e-, E_ox = .76 volts
    And the Copper would be getting reduced at the cathode,
    Cu+2 + 2e- --> Cu, E_red = .34 volts
    So,
    E_cell = (.76 + .34) volts = 1.10 volts

    If you go to the extremes on a standard reduction table and use something like Fluorine gas (E_red = 2.87 v) and Lithium metal (E_red = -3.05), the difference in reduction potentials would give you a battery voltage of 5.92 volts.
     
  4. Mar 16, 2007 #3
    I like those 5.92 volts. How will Fluorine gas be used if I want to make a battery like that, and If I ask nicely are there something higher that 5.92 volts?
     
  5. Mar 16, 2007 #4

    mrjeffy321

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    If there was an easy (and safe) way to make a battery out of Fluorine and Lithium, yielding such as high voltage, one might think it would have already been implemented.
    Fluorine gas is an extremely strong oxidizing agent and is quite dangerous. When allowed to react with Lithium metal (a powerful reducing agent) you will get a pretty spectacular reaction (think of the reaction between Sodium metal and Chlorine gas, if you have ever seen that occur, then imagine it much stronger). I don’t think it is very easy or practical to make a Li – F2 battery. Besides, how much Fluorine gas do you have anyway?

    Although there might be some more exotic compounds which will give higher, magnitude, reduction potentials (like XeF + e- --> Xe + F-), I think Lithium and Fluorine might be the highest for the elements.
     
  6. Mar 16, 2007 #5
    Yea I’ve seen on Wikipedia in standard electrode potential (data page)
    Fluorine (F) is the strongest oxidizing agent and Lithium (Li) the stronger reducing agent\\

    I don’t know Fluorine gas but isn’t oxygen an oxidizer? Fluorine an oxidizer? Do you have a list of oxidizer for me please, than chorine is probably an oxidizer two? Then in the presence of fire does Fluorine also acts as an oxidizer?
    Or does Fluorine only acts as an oxidizer then in the subjected to the presence of fire?

    Sodium metal and Chlorine gas isn’t that salt “Sodium Chloride” then combined
    Hmm yea I know Sodium metal is full of crap then near water, it’s reactive and Chlorine gas stinks, then I do experiment with salt and electricity and water and some electrodes I smell Chlorine gas, I smells unpleasant

    No, luckily I don’t have any Fluorine gas.

    Yip, that’s what I’m talking about, stuff like NaS but that’s used in the Sodium Sulfur batteries, but stuff like FeS or PbS or SnS and alloys of metals

    And in zinc-carbon batteries Manganese Oxide (MnO2 ) are used but I’ve I replace it with something like (sea sand) silicon dioxide (SiO2 ) but that 02 is two oxygen’s but why is one called Oxide and the other one dioxide.

    Manganese is a metal “transition metals”
    And Silicon is also a metal “metalloids”
     
    Last edited: Mar 16, 2007
  7. Mar 16, 2007 #6

    mrjeffy321

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    Remember what occurs in an Oxidization / Reduction reaction.

    LEO GER
    Loose Electrons Oxidization,
    Gain Electrons Reduction

    If something has a strong tendency to Gain electrons (like Chlorine, Fluorine, Oxygen, ….) they are prone to being reduced. When the substance is reduced, some other substance is oxidized. These materials which like to be reduced are called “Oxidizers” since they will Oxidize other substances while they are reduced.
    It works the other way around too.
    Substances which like to loose electrons (like Sodium, Potassium Lithium, …) are reducing agents since they reduce other materials as they are oxidized.
    The more likely a substance is to undergo reduction or oxidization, the stronger oxidizing / reducing agent it is. You should notice the general trend with where these oxidizers and reducers are on the periodic table and how this corresponds to the atom’s ‘desire’ to have a completed octet in their valance shell. Things like Fluorine and Chlorine are over on the far right of the periodic table, just 1 electron short of having a noble gas configuration. These materials would really like to be reduced in order to get that extra electron. Whereas over on the far left, where elements like Lithium and Sodium appear, they have 1 electron too many for a noble gas configuration and they would ‘like’ to be oxidized in order to loose that extra electron.

    Redox (Reduction – Oxidation) reactions always occur together….in other words, something must be oxidized (loose electrons) in order for something else to be reduced (gain electrons).
    So if you put something like Sodium (strong reducing agent) together with something like Chlorine (strong oxidizing agent) you will get a quite a vigorous reaction since the resulting products will be at a much lower energy than the reactants and that different in energy will be given off mostly in heat.


    By ‘more more exotic compounds’, I was referring to reduction reactions like,
    Sr+ + e- --> Sr
    Where a singly ionized Strontium atom is reduced to Stronium metal, which (according to my CRC book) has a standard reduction potential of -4.10 volts. This reduction potential is even lower than that of Li+ + e- --> Li, but then, where are you going to get Sr+1 ? Strontium likes to be +2
     
  8. Mar 19, 2007 #7
    Yea no doubt, I don’t think I’ll be able to get Strontium (Sr)

    So if fluorine, chlorine are oxidizers why cant our lungs handle fluorine and chorine, but only are compatible with oxygen?

    And if electric eels are capable of producing high voltages just by using sodium in a stack of cells

    And in human and animals our harts work with electrolytes, sodium and potassium and if one lowers you get high blood pressure

    I did an experiment with molten salt; it takes some to melt it without letting the salt acts like pop con. Salt starts to glow and probably burn if you ground the container and use a copper wire with 28V @ 1.5A max and drag the wire in the molten salt then still heated, if looks like lava, it glows around the wire, it actually melts the copper wire if your lucky. Does that experiment mean something?

    And how can I make salt a liquid, without working with water, and without heating it?
     
    Last edited: Mar 19, 2007
  9. Mar 19, 2007 #8
    Hi Jacquesl, in your experiment, you did not say what kind of power supply you used: DC or AC, and how you polarized if it is a DC one. Anyway I guess that if you connected the negative electrode to the copper wire, for the potential is 28 v so sodium ion will receive electrons and become metalic sodium. With that high temperature Na will react with O2 in the atmosphere strongly and you see the lava-like glow.
     
  10. Mar 19, 2007 #9
    It’s a variable DC power supply, those LM317T type 1.2 – 28v @ 1.5A max
    If I swap the 2 wires, it gives me the same effect. But if I examine the lava stuff, it’s like brown powder substance, unknown to me. It looks like very dirty brown salt finely powered, and it doesn’t give of any weird smell like chorine gas like in electrolyses of salt water. If just looks amazing then in “lava mode” if you get it to sort of oscillate like a bell, it make a small pop and starts to increase the lava glow, and of course you will have to maintain the temperature of the molten salt. +- 80% molten to for it to conduct any electricity.
     
  11. Mar 19, 2007 #10

    mrjeffy321

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    You were able to melt salt. What kind of salt? Sodium Chloride I assume. As a suggestion for the future, Sodium Hydroxide might have been a better choice. NaOH melts at a lower temperature and does not produce the Chlorine gas which is evolved when you electrolysize NaCl.
    You are going to need to raise the salt’s temperature (through heating) in order to melt it.
    Dissolving the Salt in water will give you a salt solution which will not allow the same electrolytic reaction when you run a current through it since water is much easier to reduce than Na+.
     
  12. Mar 19, 2007 #11
    Yea I also assume its Sodium Chloride (NaCl) and its ion something salt if that makes any sense.
    I don’t think I’ll be able to get Sodium Hydroxide (NaOH)

    //////////////////////////////////////////////////////////

    I’ll like to know if someone will be able to answer my previously asked questions.

    (1)
    “And in zinc-carbon batteries Manganese Oxide (MnO2 ) are used but I’ve I replace it with something like (sea sand) silicon dioxide (SiO2 ) but that 02 is two oxygen’s but why is one called Oxide and the other one dioxide”

    (2)
    “And if electric eels are capable of producing high voltages just by using sodium in a stack of cells”

    What’s the electrodes?

    ”And in humans and animals our harts work with electrolytes, sodium and potassium and if one lowers you get high blood pressure”

    How does potassium and sodium acts as an electrolyte in a human body, it creates the electricity in the human’s body?


    Then in the presence of fire does Chlorine and Fluorine also acts as an oxidizer like oxygen does?
    but why cant humans totally not breath “chlorine and fluorine” gasses but only oxygen? But all of them are oxidizers?
     
  13. Mar 20, 2007 #12

    mrjeffy321

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    The, quote-unquote, proper name for the compound MnO2 is “Manganese (IV) Oxide. Sometimes you will also see it called “Manganese Dioxide” by people using it outside what might normally be considered a chemistry situation (for example, a Pottery supply house).
    The “Di” is not technically part of the name since the number of Oxygen atoms in the compound is more or less implied when you know the charge on the Manganese ion (+4). Since Oxide ions have a -2 charge, you should be able to figure out that there will be 2, -2, Oxides for every Mn+4.

    For SiO2 (since it is not an ionic compound, but rather a molecule), we do need to specify the “Di” on the Oxide to indicate the number of Oxygens.
    Other common molecules which you should know which specify the number of Oxygens are “Carbon Dioxide” (CO2) and “Carbon Monoxide” (CO).

    I have lost all manner of ability to explain it I fear since I no longer think in terms of the ‘rules’ for naming the compounds.

    I am not entirely sure, but I would guess the outside of the little EMF producing cells. As is my understanding, they have a type of cells which act as a little battery. Many of these ‘battery’ cells are stacked on top of each other to produce a high enough potential to perform its task of stunning the prey.

    They do not “create” ‘electricity’.
    If something is an electrolyte, it means that when it is dissolved in water, it breaks into ions.
    For example, Potassium Chloride (KCl), when dissolved in water will break up into K+ and Cl- ions.
    If something is a strong electrolyte, it will break up [almost] completely into ions (whereas a weak electrolyte will hardly break up at all). Potassium and Sodium Chlorate are two examples of strong electrolytes.
    Ordinarily, water will not conduct electricity since there are no available charge carries to transmit the current (electrical current is the flow of charged particles). When an electrolyte is dissolved in the water (which out body is made up 70% of), an electrical current is allowed to flow due to the presence of all these charges particles floating around in the water.

    I would imagine that there are more requirements other than the gas we breathe in just being an oxidizer.
    Chlorine and Fluorine react in a particularly negative way with the insides of our lungs, whereas Oxygen reacts in a rather ‘nice’ way. Why this is so might be venturing over into biology and how breathing has developed over time.
     
  14. Mar 20, 2007 #13
    Interesting, so all life forms has adjusted to nature and have made use of all the available stuff in nature.

    So if we let bacteria grow on mars maybe there might be life over a couple of billion years, and maybe they all might breath on helium or on hydrogen, it would be a advantage if possible.

    This forum is starting to get seriously complicated for me, but I try to keep up,

    It’s like H20, H2S and H2SO4 and maybe HCl

    All of them contain hydrogen, but humans drink water (H20) and rather not the others, but all contains hydrogen bonded in the solution
    I know humans done like Sulfur and Chlorine
    And like I’ve seen, does batteries always contain acid? And why does Lead acid batteries contains Sulfuric acid (H2SO4) and lead that a weird combination for me

    And why not “drinkable acid” like water, and oxygen kills bacteria so it’s also dangerous but not to humans and chlorine and fluorine kills more
     
  15. Feb 9, 2010 #14
    You really need to take a course in high school chemistry.

    Water is not an acid despite being common to H2SO4 or HCl by hydrogen. Acids are more complicated than just a compound containing hydrogen. What makes HCl and H2SO4 different from water is that they have a tendency to 'let go' of a hydrogen ion.

    So when it dissolves in water there will be hydrogen ions floating around, which causes acidity. Water doesn't give off any hydrogen ions (or I think it does it in a way that they cancel out so it becomes pretty much neutral).

    Again study some chemistry. If you look at the table of elements that oxidise / reduce you will see lead up there. It doesn't matter if it seems weird, its just how nature works.

    http://www.pembinatrails.ca/shaftesbury/mrdeakin/srp table.gif

    Look at this table, 16th from the bottom you have:

    PbSO4 + 2e <-> Pb + SO4 : -0.83

    So what you see here is that (reading it backwards) Pb (lead) + SO4 (The H2 from H2SO4 is dissolved as the acid) gives you PbSO4 + 2e (or 2 electrons) giving you 0.83 volts.

    Reading it forwards, if you give PbSO4 0.83 volts it will turn back into Pb + SO4 (How recharging car batteries work)
     
    Last edited: Feb 9, 2010
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