Electrolytes, electrodes, electrolytes and electrodes materials, and manufacturing thereof

A sodium secondary battery comprising a negative electrode, a positive electrode and an electrolyte including a sodium salt and a compound having a chemical structure including an oxygen molecule covalently bound to R1 and R2 groups (R1-O—R2), wherein each of R1 and R2 is an alkyl group or an aryl group,

• wherein the negative electrode includes a plurality of tin (Sn) particles,
• wherein the plurality of Sn particles has an average particle size equal to or larger than about 1.3 μm and up to about 200 μm,
• wherein the electrolyte exhibits an ionic conductivity of from about 10−5 mS cm−1 to about 100 mS cm−1 at room temperature,
• wherein the sodium secondary battery has an N/P ratio of 0.1 to 30.0.