Optimization of electrochemical cell
A system and method for optimizing electrochemical cells including electrodes employing coordination compounds by mediating water content within a desired water content profile that includes sufficient coordinated water and reduces non-coordinated water below a desired target and with electrochemical cells including a coordination compound electrochemically active in one or more electrodes, with an improvement in electrochemical cell manufacture that relaxes standards for water content of electrochemical cells having one or more electrodes including one or more such transition metal cyanide coordination compounds.
1. An electrochemical cell, comprising:
a cell stack having a liquid electrolyte, an anode electrode, a separator, and a cathode electrode, said electrodes electrochemically communicated with said liquid electrolyte, with components of said cell stack having an as-synthesized set of properties, a pre-communication set of properties before said electrodes are electrochemically communicated with said liquid electrolyte, and a post-communication set of properties after said electrodes are electrochemically communicated with said liquid electrolyte;
wherein a first particular one electrode of said electrodes includes a transition metal cyanide coordination compound material having a composition conforming to formula I, formula I including A x P y [R(CN) 6 ] z (H 2 O) n ;
wherein A represents an alkali cation and P and R each represent a multivalent transition metal cation;
wherein 0.5<z<1;
wherein x, y, and z are related based on electrical neutrality, x>0, y>0, z>0; and
wherein n=6*(1−z)+m k , with n>0, with k=0 identifying an as-synthesized material and k=1 to 2 identifying a set of post-synthesized states for said first particular one electrode, and with 6*(1−z) identifying as a quantity of coordinated water of said compound material, and with each m k >0, each m k identifying as a quantity of interstitial water of said compound material for one of said states of said first particular one electrode, with each said quantity m k of interstitial water being equivalent to a weight percentage M k =m k *W H2O /W dry *100%, with W H2O being the molecular weight of water and W dry being the molecular weight for the composition of formula I excluding all of its water content, with M 0 identifying as an as-synthesized set of properties for said first particular one electrode, with M 1 identifying as a pre-communication set of properties for said first one particular electrode, with M 2 identifying as a post-communication set of properties for said first particular one electrode; and
wherein said liquid electrolyte includes a polar organic solvent combined with an alkali metal salt and water having a water concentration, said water concentration including a pre-communication water concentration c1 and including a post-communication water concentration c2 and wherein c1>c2;
wherein said as-synthesized set of properties includes M 0 up to 45% for a set of as-synthesized materials, said set of as-synthesized materials including said composition of formula I;
wherein said M 1 includes a range between 1% and 12% for a set of electrode materials of said first particular one electrode, said set of electrode materials including said composition of formula I; and
wherein M 2 >M 1 .
2. The electrochemical cell of claim 1 wherein said first particular one electrode includes said anode electrode.
3. The electrochemical cell of claim 1 wherein said first particular one electrode includes said cathode electrode.
4. The electrochemical cell of claim 1 wherein a second particular one electrode of said electrodes does not include a transition metal cyanide coordination compound material having a composition conforming to formula I.
5. The electrochemical cell of claim 2 wherein a second particular one electrode of said electrodes includes said cathode electrode and wherein said cathode electrode does not include a transition metal cyanide coordination compound material having a composition conforming to formula I.
6. The electrochemical cell of claim 2 wherein a second particular one electrode of said electrodes includes said anode electrode and wherein said anode electrode does not include a transition metal cyanide coordination compound material having a composition conforming to formula I.
7. The electrochemical cell of claim 1 with c1<1,000 ppm and with c2<100 ppm.
8. The electrochemical cell of claim 1 with c1<1,000 ppm and with c2<20 ppm.
9. The electrochemical cell of claim 1 wherein said polar organic solvent includes a mononitrile.
10. The electrochemical cell of claim 9 wherein said liquid electrolyte includes a dinitrile as an additive.