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. A method for assembling an electrochemical cell, comprising:
a step of assembling a cell stack having a liquid electrolyte including a quantity of water, a first electrode, a separator, and a second electrode, said electrodes communicated with said liquid electrolyte during said step of assembling, with components of said cell stack having an as-synthesized set of properties, a pre-assembly set of properties before said electrodes are communicated with said liquid electrolyte, and a post-communication set of properties after said electrodes are communicated with said liquid electrolyte, wherein said sets of properties each include a water concentration of said liquid electrolyte and a quantity of component water in a component coupled to said liquid electrolyte of said cell stack;
a step of coupling, during said step of assembling, said liquid electrolyte to said component; and
a step of transferring, during said step of coupling, a post-assembly quantity of electrolytic water to said quantity of component water; and
a step of reducing, responsive to said step of transferring, said water concentration of said liquid electrolyte.
2. The method of claim 1 wherein said water concentration of said liquid electrolyte of said pre-assembly set of properties includes a concentration c1 with said concentration c1<1,000 ppm, and wherein said water concentration of said liquid electrolyte of said post-communication set of properties includes a concentration c2 with said concentration c2<100 ppm.
3. The method of claim 1 wherein said water concentration of said liquid electrolyte of said pre-assembly set of properties includes a concentration c1 with said concentration c1<1,000 ppm, and wherein said water concentration of said liquid electrolyte of said post-communication set of properties includes a concentration c2 with said concentration c2<20 ppm.
4. The method of claim 1 wherein said component includes at least one electrode of said electrodes and wherein said at least one electrode contains an active material including a transition metal cyanide coordination compound material.
5. The method of claim 1 wherein said component includes said first electrode and said second electrode and wherein each electrode contains an active material including 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; and
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 as an as-synthesized material and k=1 to 4 identifying as a set of post-synthesized states for each 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 each 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 of said composition conforming to formula I excluding all of its water content, with each electrode including an M 0 identifying as an as-synthesized set of properties for each electrode, with M 1 identifying as a pre-communication set of properties for said first electrode, with M 2 identifying as a pre-communication set of properties for said second electrode, with M 3 identifying as a post-communication set of properties for said first electrode, and with M 4 identifying as a post-communication set of properties for said second 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, for each electrode, M 0 up to 45% for a set of as-synthesized materials, said set of as-synthesized materials including said composition conforming to formula I;
wherein said M 1 includes a range between 1% and 12% for a set of first electrode materials of said first electrode with M 1 ≤M 3 , said set of first electrode materials including said composition conforming to formula I;
wherein said M 2 includes a range between 1% and 12% for a set of second electrode materials of said second electrode with M 2 ≤M 4 , said set of second electrode materials including said composition conforming to formula I and
wherein M 3 +M 4 >M 1 +M 2 .
6. The method of claim 5 wherein said first electrode includes an anode electrode.
7. The method of claim 6 wherein said second electrode includes a cathode electrode.
8. The method of claim 7 wherein both said anode electrode and said cathode electrode include a composition conforming to formula I and wherein said composition conforming to formula I for said cathode electrode is different from said composition conforming to formula I for said anode electrode.