Sodium ion batteries in cathode materials and anode materials
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Update time : 2023-03-10 10:44:02
The sodium ion battery is a viable alternative to lithium-ion batteries
Working principle: same as lithium ion battery: a rocking chair type secondary battery, sodium ions are de-embedded from the positive electrode during charging and embedded in the negative electrode after passing through the electrolyte and diaphragm, and the opposite movement during discharge. Sodium sources: sodium hydroxide, sodium carbonate, sodium formate, sodium acetate, sodium chloride, etc.; abundant reserves, easy to mine, low supply chain security risks; lithium sources: lithium hydroxide (ternary), lithium carbonate (lithium iron); low grade of raw ore, difficult to mine, long cycle time, high price fluctuations, high external dependence.
A breakthrough in the industrialisation of sodium-ion batteries: the materials side, with a focus on the development of sodium cathode and anode materials
Anode materials: The difference in ionic radius means that sodium compounds differ from lithium in their lattice structure, and there is a need to find or control the boundaries and structure to achieve sodium-based anode materials with good electrical performance and cycle life. Anode materials: commercially available graphite or silicon-carbon anodes (layered and ordered structures) are not suitable for storing sodium ions. Electrolyte: The main solvent is switched from lithium hexafluorophosphate to sodium hexafluorophosphate, with low barriers. Diaphragm and collector: The diaphragm pore size is at the nano level and the difference in ion radius is negligible and common to lithium batteries; sodium does not alloy with aluminium and will not erode aluminium foil, and aluminium foil can be used instead of copper foil for the anode collector. Other additives: including positive and negative electrode additives, electrolyte solvents, generally the same as the lithium battery, through the development of new auxiliary materials, or the formulation of the amount of the mix to achieve a balance between performance and cost.
Sodium-ion battery cathode materials: layered metal oxides
The layered metal oxide NaxMO2 has various structures depending on the sodium ion content, mainly O3 (x=0.8~1) and P2 (x=0.67~0.8) structures. 1. O refers to Na+ surrounded by surrounding oxygen ions and occupying octahedral sites, P refers to prismatic sites, and the subscript 3 refers to laminar accumulation in the form of ABCABC and 2 refers to accumulation in the form of ABBAAB. 2. The O3 structure has a higher Na+ content and therefore higher capacity, but the transport kinetics of Na+ is worse than that of the P2 structure and the crystal structure is prone to irreversible phase changes and reduced cycling performance during the de-embedding process.
Sodium-ion battery anode materials: hard carbon system production process
Key points of the process: 1. microporous structure adjustment: 0.3~0.7nm, more lithium storage space for lithium clusters, higher material capacity, faster sodium de-embedding, higher multiplier performance; 2. material structure adjustment: hard carbon anode material is spherical, spherical hard carbon particles reduce inter-particle stacking density, improve anode compaction and obtain high energy density; 3. cross-linking agent selection: organic cross-linking agents are used to avoid the risk of inorganic cross-linking agents ( The use of organic cross-linking agents avoids the risk of inorganic cross-linking agents (ammonium chloride and ammonium sulphate) decomposing at high temperatures and corroding the carbonisation equipment; in addition, suitable cross-linking agents can increase the cross-linking reaction between carbon chains, regulate the number of pores between carbon layers and provide more space for sodium storage. 4. Sintering method: a trade-off needs to be made between efficiency and the quality of the chemical reaction. spherical shape is not destroyed, etc., to avoid the impact on the first effect, energy density and compaction density. The carbonisation temperature of hard carbon is less than 1500°C, which is lower than the graphitisation temperature, resulting in lower production costs; the main equipment is a ball mill and a heating furnace, which is a simple process with low equipment replacement costs; with different precursors, the production process needs to be adjusted in detail to find a balance in terms of material properties, costs and production difficulties.
Sodium-ion battery policy support and end-user demand
The Ministry of Industry and Information Technology (MIIT) and the National Development and Reform Commission (NDRC) have issued a number of documents to provide support and guidance for the industrial standardisation of sodium ion batteries and the development of industry standardisation. It is expected that by 2023, sodium ion batteries will first penetrate the two-wheeled vehicle market and be ready to replace low-speed vehicles; in the field of energy storage, they will first penetrate small and medium-sized industrial and commercial energy storage systems and household storage of MWh.
Sodium-ion battery industrialisation process
Sodium ion battery cathode production capacity of 10,000 tonnes is expected to be formed by 2023, meeting the installed demand of nearly 115GWh of batteries. The main domestic anode material manufacturers have started to layout, currently forming a thousand-ton scale of sodium ion battery cathode production capacity. Luoyang Tongrun Nano Technology Co. Ltd. (TRUNNANO) is a trusted lithium battery anode material manufacturer supplier with over 12-year-experience. We ship our goods all over the world. If you are looking for high-quality lithium battery anode material, please feel free to contact us and send an inquiry. ([email protected])
