Provided herein are compositions and methods for quantifying polyphosphates. In particular, provided herein are solution and substrate based assays for quantifying polyphosphates in complex samples.

An energy storage composition can be used as a new Na-ion battery cathode material. The energy storage composition with an alluaudite phase of A.sub.xT.sub.y(PO4).sub.z, Na.sub.xT.sub.y(PO4).sub.z, Na.sub.1.702Fe.sub.3(PO4).sub.3 and Na.sub.0.872Fe.sub.3(PO4).sub.3, is described including the hydrothermal synthesis, crystal structure, and electrochemical properties. After ball milling and carbon coating, the compositions described herein demonstrate a reversible capacity, such as about 140.7 mAh/g. In addition these compositions exhibit good cycling performance (93% of the initial capacity is retained after 50 cycles) and excellent rate capability. These alluaudite compounds represent a new cathode material for large-scale battery applications that are earth-abundant and sustainable.

An energy storage composition can be used as a new Na-ion battery cathode material. The energy storage composition with an alluaudite phase of A.sub.xT.sub.y(PO4).sub.z, Na.sub.xT.sub.y(PO4).sub.z, Na.sub.1.702Fe.sub.3(PO4).sub.3 and Na.sub.0.872Fe.sub.3(PO4).sub.3, is described including the hydrothermal synthesis, crystal structure, and electrochemical properties. After ball milling and carbon coating, the compositions described herein demonstrate a reversible capacity, such as about 140.7 mAh/g. In addition these compositions exhibit good cycling performance (93% of the initial capacity is retained after 50 cycles) and excellent rate capability. These alluaudite compounds represent a new cathode material for large-scale battery applications that are earth-abundant and sustainable.

An equilibrium solution, such as a beverage product, containing a calcium salt of a sequestrant (such as calcium hexametaphosphate), coordinated compound of a calcium sequestrant and a sequestrant allows the delivery of bio-available calcium while maintaining the preservative qualities of the sequestrant (such as sodium hexametaphosphate). In one embodiment, the reaction of a salt such as calcium hydroxide and a sequestrant such as sodium potassium hexametaphosphate (sodium potassium polyphosphate) yields such an equilibrium solution in a beverage matrix. Calcium hexametaphosphate having a relatively short phosphate chain is disclosed, as well as the method of making that material, and beverage compositions containing the material together with a sequestrant preservative, such as SHMP.

An energy storage composition can be used as a new Na-ion battery cathode material. The energy storage composition with an alluaudite phase of A.sub.xT.sub.y(PO4).sub.z, Na.sub.xT.sub.y(PO4).sub.z, Na.sub.1.702Fe.sub.3(PO4).sub.3 and Na.sub.0.872Fe.sub.3(PO4).sub.3, is described including the hydrothermal synthesis, crystal structure, and electrochemical properties. After ball milling and carbon coating, the compositions described herein demonstrate a reversible capacity, such as about 140.7 mAh/g. In addition these compositions exhibit good cycling performance (93% of the initial capacity is retained after 50 cycles) and excellent rate capability. These alluaudite compounds represent a new cathode material for large-scale battery applications that are earth-abundant and sustainable.

A process for producing a phosphate by: introducing oxidic metal(II)-, metal(III)- metal(IV) or compounds with mixed oxide stages selected from hydroxides, oxides, oxide-hydroxides, oxide-hydrates, carbonates and hydroxide carbonates, of at least one of the metals Mn, Fe, Co and Ni with the elemental forms or alloys of at least one of the metals Mn, Fe, Co and/or Ni into an aqueous medium containing phosphoric acid, and reacting the oxidic metal compounds with elemental forms or alloys of the metals to obtain divalent metal ions, removing solid substances, producing an alkali metal phosphate receiver solution with a pH-value of 5 to 8 and metering the aqueous solution into the receiver solution and at the same time metering a basic aqueous alkali hydroxide solution that the pH-value of the resulting reaction mixture is kept in the region of 5 to 8 to precipitate the desired phosphate.

A process for producing a phosphate by: introducing oxidic metal(II)-, metal(III)- metal(IV) or compounds with mixed oxide stages selected from hydroxides, oxides, oxide-hydroxides, oxide-hydrates, carbonates and hydroxide carbonates, of at least one of the metals Mn, Fe, Co and Ni with the elemental forms or alloys of at least one of the metals Mn, Fe, Co and/or Ni into an aqueous medium containing phosphoric acid, and reacting the oxidic metal compounds with elemental forms or alloys of the metals to obtain divalent metal ions, removing solid substances, producing an alkali metal phosphate receiver solution with a pH-value of 5 to 8 and metering the aqueous solution into the receiver solution and at the same time metering a basic aqueous alkali hydroxide solution that the pH-value of the resulting reaction mixture is kept in the region of 5 to 8 to precipitate the desired phosphate.

The invention relates to electrodes that contain active materials of the formula: Na.sub.aX.sub.bM.sub.cM.sub.d(condensed polyanion).sub.e(anion).sub.f; where X is one or more of Na+, Li+ and K+; M is one or more transition metals; M is one or more non-transition metals; and where a>b; c>0; d0; e1 and f0. Such electrodes are useful in, for example, sodium ion battery applications.

The invention relates to electrodes that contain active materials of the formula: Na.sub.aX.sub.bM.sub.cM.sub.d(condensed polyanion).sub.e(anion).sub.f; where X is one or more of Na+, Li+ and K+; M is one or more transition metals; M is one or more non-transition metals; and where a>b; c>0; d0; e1 and f0. Such electrodes are useful in, for example, sodium ion battery applications.