The sodium-ion battery mainly includes five parts: cathode electrode material, anode electrode material, battery electrolyte, battery current collector and battery separator.

Cathode electrode material

Cathode and anode materials affect key performance indicators such as energy density, power density, cycle life, and safety of Na-ion batteries, and are critical to battery performance.

The mainstream sodium-ion battery cathode materials can be divided into layered metal oxides, polyanionic compounds and Prussian blue compound systems.

Anode material

Different from the graphite material negative electrode used in lithium-ion batteries, due to the too small spacing between graphite layers, sodium ions with larger radius need more energy to intercalate between graphite layers.Reversible deintercalation cannot be performed within the effective potential window, so it is considered that conventional graphite cannot be used as the anode of Na-ion batteries.

The research directions of anode materials for sodium ion batteries include hard carbon, soft carbon, titanium-based oxides and alloys, etc. The research on hard carbon is the most, and the current commercial sodium ion batteries also use hard carbon materials as negative electrodes.

Battery separator

At present, the electrolyte composition of the most common organic electrolyte-based sodium-ion battery is very similar to that of lithium-ion battery, and the solvent remains unchanged.

Only the solute salt is changed from lithium battery material LiPF6 to sodium NaPF6 and the separator can use the same separator as the lithium-ion battery.

The separator is used to isolate the positive and negative electrodes of sodium-ion batteries, preventing short-circuit phenomena, and at the same time acting as an ion channel.

Sodium-ion batteries electrolyte

Electrolytes are ionic charge carriers necessary for electrochemical reactions to occur and are the key to improving the power characteristics of Na-ion batteries. Electrolytes are mainly composed of solvents, solutions, additives and the like. The most common electrolyte for sodium-ion batteries is an organic liquid electrolyte. The organic solvent portion of the organic electrolyte is similar to the corresponding composition of lithium-ion batteries.

Current collector material

The current collector aluminum foil of sodium ion battery is basically the same as that of lithium battery, and the performance requirements are basically similar.