Non-flammable sodium-ion batteries

1. A non-flammable sodium-ion battery comprising:

a cathode for the sodium-ion battery;

an anode for the sodium-ion battery;

a separator; and

an electrolyte comprising a salt and a glyme solvent selected from the group consisting of tetraglyme and an analogue thereof, wherein:

the anode does not comprise lithium;

the salt comprises NaBF 4 ;

the NaBF 4 is provided at a concentration of from 0.5 M to 2.0 M in the glyme solvent;

the battery has an average voltage of from 1.5 V to 6.0 V;

the battery has a coulombic efficiency after 5 charge/discharge cycles of at least 97%; and

the cathode and anode comprise active material pairs selected from the group consisting of:

Zn-doped Na 3 V 2 (PO 4 ) 3 (NVP)//hard carbon, Na 0.9 [Cu 0.12 Ni 0.10 Fe 0.30 Mn 0.43 Ti 0.05 ]O 2 //hard carbon, and Na 0.9 [Cu 0.12 Ni 0.10 Fe 0.30 Mn 0.43 Ti 0.05 ]O 2 //graphite.

2. The battery according to claim 1 , wherein the average voltage is from 1.75 to 5.5 V.

3. The battery according to claim 1 , wherein the battery has a cycle life of from 50 cycles to 25,000 charge/discharge cycles.

4. The battery according to claim 1 , wherein the electrolyte further comprises one or more solvents selected from the group consisting of a cyclic carbonate, a linear carbonate, a cyclic ester, a linear ester, a cyclic or linear ether other than a glyme, a nitrile, dioxolane or a derivative thereof, ethylene sulfide, sulfolane, and sultone or a derivative thereof.

5. The battery according to claim 4 , wherein the electrolyte further comprises one or more solvents selected from the group consisting of propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, tetrahydrofuran, sulfolane, and acetonitrile.

6. The battery according to claim 1 , wherein the salt further comprises one or more salts selected from the group consisting of NaCN, NaClO 4 , NaAsF 6 , NaPF 6 , NaPF 6-x (C n F 2n+1 ) x (1<x<6, n=1 or 2), NaSCN, NaBr, NaI, Na 2 SO 4 , Na 2 B 10 Cl 10 , NaCl, NaF, NaPF 4 , NaOCN, Na(CF 3 SO 3 ), NaN(CF 3 SO 2 ) 2 , NaN(FSO 2 ) 2 , NaN(C 2 F 5 SO 2 ) 2 , NaN(CF 3 SO 2 )(C 4 F 9 SO 2 ), NaC(CF 3 SO 2 ) 3 , NaC(C 2 F 5 SO 2 ) 3 , (CH 3 ) 4 NBF 4 , (CH 3 ) 4 NBr, (C 2 H 5 ) 4 NClO 4 , (C 2 H 5 ) 4 NI, (C 3 H 7 ) 4 NBr, (n-C 4 H 9 ) 4 NClO 4 , (n-C 4 H 9 ) 4 NI, (C 2 H 5 ) 4 N-maleate, (C 2 H 5 ) 4 N-benzoate, (C 2 H 5 ) 4 N-phtalate, sodium stearyl sulfonate, sodium octyl sulfonate, and sodium dodecylbenzene sulfonate, optionally wherein the salt further comprises one or more salts selected from the group consisting of NaClO 4 , NaPF 6 , NaSCN, NaBr, NaI, NaCl, NaOCN, Na(CF 3 SO 3 ), NaN(CF 3 SO 2 ) 2 , and NaCN.

7. The battery according to claim 6 , wherein each of the one or more salts of claim 6 , when present, are provided in a concentration of greater than 0 to 2.5 M.

8. The battery according to claim 1 , wherein the electrolyte further comprises an additive selected from one or more of the group consisting of fluoroethylene carbonate (FEC), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), and adiponitrile.

9. The battery according to claim 1 , wherein the analogue of tetraglyme is selected from the compounds where one or both of the —CH 3 end members in a tetraglyme molecule are modified to either —C 2 H 5 or to —CH 2 CH 2 Cl.

10. The battery according to according to claim 1 , wherein the cathode and anode comprise the active material pair.

11. The battery according to claim 1 , wherein the cathode and anode comprise the active material pair Na 0.9 [Cu 0.12 Ni 0.10 Fe 0.30 Mn 0.43 Ti 0.05 ]O 2 //hard carbon.

12. The battery according to claim 1 , wherein the cathode and anode comprise the active material pair Na 0.9 [Cu 0.12 Ni 0.10 Fe 0.30 Mn 0.43 Ti 0.05 ]O 2 //graphite.