Anodes for sodium-ion batteries

A method for forming an anode of a sodium ion battery, the method comprising:

• a) placing a red phosphorus precursor and a graphene oxide precursor in a reaction chamber;
• b) establishing a reducing environment in the reaction chamber;
• and
• c) heating the red phosphorus precursor and a graphene oxide precursor to a first temperature that is sufficient temperature to form a composite of red phosphorus and reduced graphene oxide, wherein red phosphorus deposition and graphene oxide reduction are completed simultaneously in a single-step heat treatment.

A method for forming an anode of a sodium ion battery, the method comprising:

• a) arranging red phosphorus powder and graphene oxide powder in a layered structure having alternating layers of phosphorus powder and graphene oxide;
• b) heat treating the layered structure at a first temperature to form a red phosphorus/reduced graphene oxide combination film;
• c) placing the red phosphorus/reduced graphene oxide combination film on a substrate;
• and
• d) applying a pressure to the red phosphorus/reduced graphene oxide combination film that is sufficient to convert red phosphorus to black phosphorus such that a black phosphorus/reduced graphene oxide combination film is formed, the pressure being greater than or equal to about 5 GPa.

A sodium ion battery comprising:

• an electrolyte disposed in a container;
• a cathode at least partially immersed in the electrolyte;
• and
• an anode at least partially immersed in the electrolyte, wherein the anode includes a component selected from the group consisting of a red phosphorus-reduced graphene oxide composite having red phosphorus nanodots disposed over reduced graphene oxide substrates, a layered black phosphorus graphene composite, a layered black phosphorus graphene composite, and combinations thereof.