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 the steps of:
assembling a cell stack having a liquid electrolyte including a quantity of electrolytic water, an anode electrode, a separator, and a cathode electrode, said electrodes electrochemically communicated with said liquid electrolyte during said assembling step, with components of said cell stack having an as-synthesized set of properties, a pre-assembly 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 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;
coupling, during said assembling step, said liquid electrolyte to said component; and
transferring, during said coupling step, a post-assembly quantity of electrolytic water to said quantity of component water; and
reducing, responsive to said transferring step, 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 c 1 with said concentration c 1 <1,000 ppm, and wherein said water concentration of said liquid electrolyte of said post-communication set of properties includes a concentration c 2 with said concentration c 2 <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 c 1 with said concentration c 1 <1,000 ppm, and wherein said water concentration of said liquid electrolyte of said post-communication set of properties includes a concentration c 2 with said concentration c 2 <20 ppm.
4. The method of claim 1 wherein said component includes at least one 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 anode electrode and said cathode electrode and wherein each of said electrodes 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 particular electrode of said electrodes, 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 particular 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 each particular one of said electrodes including an M 0 identifying as an as-synthesized set of properties for said particular electrode, with M 1 identifying as a pre-communication set of properties for said anode electrode, with M 2 identifying as a pre-communication set of properties for said cathode electrode, with M 3 identifying as a post-communication set of properties for said anode electrode, and with M 4 identifying as a post-communication set of properties for said cathode 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 c 1 and including a post-communication water concentration c 2 and wherein c 1 >c 2 ;
wherein said as-synthesized set of properties includes, for each said particular electrode, 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 anode electrode materials of said anode electrode with M 1 ≤M 3 , said set of anode electrode materials including said composition of formula I
wherein said M 2 includes a range between 1% and 12% for a set of cathode electrode materials of said cathode electrode with M 2 ≤M 4 , said set of cathode electrode materials including said composition of formula I and
wherein M 3 +M 4 >M 1 +M 2 .