Disclosed herein is a class of co-ordination framework materials having various useful properties. The co-ordination frameworks comprise complexes of M.sub.2[M(CN).sub.6] or A.sub.x(M.sub.2[M(CN).sub.6]), wherein M is selected from V, Cr, Mn, Fe, Co, Ni, Cu, Ag, Au, Zn, Ru, Rh, Pd and Pt; M is selected from Fe and Ru; A (when present) is located in the pores of the framework and is selected from Li.sup.+, Na.sup.+, K.sup.+, Be.sup.2+, Mg.sup.2+ and Ca.sup.2+; and x (when present) is 0<x?8. Also disclosed are methods of making said materials and various uses of said materials.

A system and method implementing and manufacturing transition metal cyanide coordination compounds (TMCCC) comprising Na, Fe, Mn, C, H, N, S, and O, wherein the TMCCC have 0-14% hexacyanometallate vacancies such as for application in electrochemical cells, including sodium ion secondary batteries; further including both sodium and potassium with and without sulfate.

A system and method implementing and manufacturing transition metal cyanide coordination compounds (TMCCC) comprising Na, Fe, Mn, C, H, N, S, and O, wherein the TMCCC have 0-14% hexacyanometallate vacancies such as for application in electrochemical cells, including sodium ion secondary batteries; further including both sodium and potassium with and without sulfate.

A system and method implementing and manufacturing transition metal cyanide coordination compounds (TMCCC) comprising Na, Fe, Mn, C, H, N, S, and O, wherein the TMCCC have 0-14% hexacyanometallate vacancies such as for application in electrochemical cells, including sodium ion secondary batteries.

A system and method implementing and manufacturing transition metal cyanide coordination compounds (TMCCC) comprising Na, Fe, Mn, C, H, N, S, and O, wherein the TMCCC have 0-14% hexacyanometallate vacancies such as for application in electrochemical cells, including sodium ion secondary batteries.

Methods are presented for synthesizing metal cyanometallate (MCM). A first method provides a first solution of A.sub.XM2.sub.Y(CN).sub.Z, to which a second solution including M1 is dropwise added. As a result, a precipitate is formed of A.sub.NM1.sub.PM2.sub.Q (CN).sub.R..sub.FH.sub.2O, where N is in the range of 1 to 4. A second method for synthesizing MCM provides a first solution of M2.sub.C(CN).sub.B, which is dropwise added to a second solution including M1. As a result, a precipitate is formed of M1[M2.sub.S(CN).sub.G].sub.1/T..sub.DH.sub.2O, where S/T is greater than or equal to 0.8. Low vacancy MCM materials are also presented.

Methods are presented for synthesizing metal cyanometallate (MCM). A first method provides a first solution of A.sub.XM2.sub.Y(CN).sub.Z, to which a second solution including M1 is dropwise added. As a result, a precipitate is formed of A.sub.NM1.sub.PM2.sub.Q (CN).sub.R..sub.FH.sub.2O, where N is in the range of 1 to 4. A second method for synthesizing MCM provides a first solution of M2.sub.C(CN).sub.B, which is dropwise added to a second solution including M1. As a result, a precipitate is formed of M1[M2.sub.S(CN).sub.G].sub.1/T..sub.DH.sub.2O, where S/T is greater than or equal to 0.8. Low vacancy MCM materials are also presented.

A system, method, and articles of manufacture for a surface-modified transition metal cyanide coordination compound (TMCCC) composition, an improved electrode including the composition, and a manufacturing method for the composition which may include multiple chelation species (Che_x). The composition, compound, device, and uses thereof according to A.sub.xMn.sub.(y-k)M.sup.j.sub.k[Mn.sup.m(CN).sub.(6-p-q)(NC).sub.p(Che_I).sup.r.sub.q].sub.z. CHE_GROUP (Vac).sub.(1-z).nH.sub.2O, wherein CHE_GROUP includes one or more chelation materials selected from the group consisting of (Che_I).sup.r.sub.w, (Che_II).sup.s.sub.v, and combinations thereof, and wherein 0<j4, 0k0.1, 0(p+q)6, 0<x4, 0<y1, 0<z1, 0<w0.2; 3r3; 0<v0.2; 3s3; and 0n6; wherein x+2(yk)+jk+(m+(r+1)q6)z+wr+vs=0.

A system, method, and articles of manufacture for a surface-modified transition metal cyanide coordination compound (TMCCC) composition, an improved electrode including the composition, and a manufacturing method for the composition which may include multiple chelation species (Che_x). The composition, compound, device, and uses thereof according to A.sub.xMn.sub.(y-k)M.sup.j.sub.k[Mn.sup.m(CN).sub.(6-p-q)(NC).sub.p(Che_I).sup.r.sub.q].sub.z. CHE_GROUP (Vac).sub.(1-z).nH.sub.2O, wherein CHE_GROUP includes one or more chelation materials selected from the group consisting of (Che_I).sup.r.sub.w, (Che_II).sup.s.sub.v, and combinations thereof, and wherein 0<j4, 0k0.1, 0(p+q)6, 0<x4, 0<y1, 0<z1, 0<w0.2; 3r3; 0<v0.2; 3s3; and 0n6; wherein x+2(yk)+jk+(m+(r+1)q6)z+wr+vs=0.

The present application provides a positive electrode active material which may be in a particulate form and comprise a compound represented by Formula 1:
Na.sub.xA.sub.yM1[M2(CN).sub.6].sub..Math.zH.sub.2OFormula 1 wherein, A is selected from at least one of an alkali metal element and an alkaline earth metal element, and the ionic radius of A is greater than the ionic radius of sodium; M1 and M2 are each independently selected from at least one of a transition metal element, 0<y0.2, 0<x+y2, 0<1, and 0z10; and the particles of the positive electrode active material may have a gradient layer in which the content of the A element decreases from the particle surface to the particle interior.