Recently, CATL will launch sodium ion battery news many times on the headlines of the media, nano ion battery has also aroused the focus of the market.
In fact, nano-ion batteries are not new. sodium ion battery (Sodium-ion battery), also a secondary battery (rechargeable battery), mainly depends on the sodium ion moving between the positive and negative electrodes to work, similar to the lithium ion battery working principle.
The Na+ is embedded and removed between the two electrodes during charge and discharge: when charging, the Na+ is deintercalated from the positive electrode and embedded into the negative electrode through the electrolyte; the opposite is true when discharging.
that is, sodium ion batteries, with the aid of sodium ion transfer (rather than lithium ions) to store and release electrical energy.
The electrode material used in sodium ion batteries is mainly sodium salt, which is richer and cheaper than lithium salt. Because sodium ions are larger than lithium ions, sodium ion batteries are a cost-effective alternative when the weight and energy density are not high.
Compared with lithium ion batteries, sodium ion batteries have the advantages of:
(1) The raw material of sodium salt is rich in reserves and low in price. Compared with the ternary cathode material of lithium ion battery, the cost of raw material is reduced by half;
(2) The use of low-concentration electrolytes (the same concentration of electrolytes, which have conductivity higher than about 20 per cent of lithium electrolyte) is allowed to reduce costs due to the characteristics of sodium salts;
(3) The sodium ion does not form an alloy with aluminum, and the negative electrode can use aluminum foil as the collecting fluid, which can further reduce the cost by about 8% and the weight by about 10%;
(4) Sodium ion batteries are allowed to discharge to zero volts due to their non-over-discharge characteristics. Wh/kg, the energy density of sodium ion battery is more than 100, it is comparable to that of lithium iron phosphate battery, but its cost advantage is obvious, which is expected to replace the traditional lead acid battery in large-scale energy storage.
The study of sodium ion batteries began in the 1980s. The electrochemical properties of electrode materials such as MoS2、TiS2 and NaxMO2 were not ideal and the development was very slow. Finding suitable sodium ion electrode material is one of the key points to realize practical application of sodium ion energy storage battery.
Since 2010, a series of positive and negative electrode materials have been designed and developed according to the characteristics of sodium ion batteries, which have greatly improved their capacity and cycle life, such as hard carbon materials as negative electrodes, transition metals and their alloy compounds, polyclonal subclasses as positive electrodes, Prussian blue, oxide materials, especially layered structure NaxMO2(M =Fe、Mn、Co、V、Ti) and binary and ternary materials, which show good charge-discharge specific capacity and cycle stability.
Because sodium ions are relatively large and require more energy to drive the movement of ions, this was once the biggest headache for new battery technology until scientists, like carbon core batteries, used carbon as a driving medium. Sodium ion batteries can be as efficient as lithium batteries seven times, and can be recycled more times. In addition, the problem of liquid memory of sodium ions has been overcome.
However, despite the rich resources, Ningde era also said that the current nano-ion battery, compared with the large-scale application of lithium ion batteries, the cost will be slightly more expensive.
