Na-rich electrolyte compositions provided herein can be used in a variety of devices, such as sodium ionic batteries, capacitors and other electrochemical devices. Na-rich electrolyte compositions provided herein can have a chemical formula of Na3OX, Na3SX, Na (3-δ) Mδ/2OX and Na (3-δ) Mδ/2SX wherein 0<δ<0.8, wherein X is a monovalent anion selected from fluoride, chloride, bromide, iodide, H−, CN−, BF4−, BH4−, ClO4−, CH3−, NO2−, NH2− and mixtures thereof, and wherein M is a divalent metal selected from the group consisting of magnesium, calcium, barium, strontium and mixtures thereof. Na-rich electrolyte compositions provided herein can have a chemical formula of Na (3-δ) Mδ/3OX and/or Na (3-δ) Mδ/3SX; wherein 0<δ<0.5, wherein M is a trivalent cation M3, and wherein X is selected from fluoride, chloride, bromide, iodide, H−, CN−, BF4−, BH4−, ClO4−, CH3−, NO2−, NH2− and mixtures thereof. Synthesis and processing methods of NaRAP compositions for battery, capacitor, and other electrochemical applications are also provided.