Sodium-ion battery
Encyclopedia
Sodium-ion batteries are a type of reusable battery
that uses sodium
-ions as a way to store power in a compact system. This type of battery is still in a developmental phase but is forecasted to be a cheaper, more durable way to store energy
than commonly used lithium-ion batteries. Unlike sodium-sulfur batteries
, sodium ion batteries can be made portable and are able to work at room temperature
(approx. 25˚C).
containing the charger and into the anode of the battery. During discharge the same process occurs but in the opposite direction. Once a circuit
is completed electrons pass back from the anode to the cathode and the Na+ ions travel back to the anode.
is in short supply, where as sodium is much more abundant. If the modern day batteries were switched over to a sodium-ion cell it would greatly lower the price of the product. Researchers like Jay Whitacre, at Carnegie Mellon University
, say that the sodium cell would also be able to store more energy which would make it a better option for storing reusable energy at solar and wind farms.
. Researchers are now looking at different anode and cathode materials that will allow a sodium cell to maintain its original capacity.
NaF + (1−x)VPO4 + xCrPO4 → NaV1−xCrxPO4F
the introduction of the Cr
helped the battery retain more energy through cycles of charge and discharge. The chart below (from their study) shows the differences between the battery with and without Cr
.
of the two cathode materials. They found the sodium
iron
phosphate
cathode easily replaces a lithium
iron
phosphate
in a Li cell. The combined lithium-ion and sodium-ion make up would lower the overall price of the battery.
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...
that uses sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
-ions as a way to store power in a compact system. This type of battery is still in a developmental phase but is forecasted to be a cheaper, more durable way to store energy
Energy
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
than commonly used lithium-ion batteries. Unlike sodium-sulfur batteries
Sodium-sulfur battery
A sodium–sulfur battery or liquid metal battery is a type of molten metal battery constructed from sodium and sulfur . This type of battery has a high energy density, high efficiency of charge/discharge and long cycle life, and is fabricated from inexpensive materials...
, sodium ion batteries can be made portable and are able to work at room temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
(approx. 25˚C).
Energy Storage
A sodium ion battery stores energy in chemical bonds in its cathode. When the battery is charging Na+ ions de-intercalate and migrate towards the anode. Meanwhile charge balancing electrons pass from the cathode through the external circuitElectronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...
containing the charger and into the anode of the battery. During discharge the same process occurs but in the opposite direction. Once a circuit
Electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...
is completed electrons pass back from the anode to the cathode and the Na+ ions travel back to the anode.
Benefits
Currently lithium-ion batteries are the preferred portable battery for most electronic devices and hybrid cars. Unfortunately, lithiumLithium
Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly...
is in short supply, where as sodium is much more abundant. If the modern day batteries were switched over to a sodium-ion cell it would greatly lower the price of the product. Researchers like Jay Whitacre, at Carnegie Mellon University
Carnegie Mellon University
Carnegie Mellon University is a private research university in Pittsburgh, Pennsylvania, United States....
, say that the sodium cell would also be able to store more energy which would make it a better option for storing reusable energy at solar and wind farms.
Research
A normal sodium cell voltage is 3.6 volts and is able to maintain 115 mA·hr g-1 after 50 cycles. Which means the battery approximately has a storage capacity of 400 W·hr kg-1 Yet, sodium-ion batteries are still unable to maintain a strong charge after repeated charge and discharge. After 50 cycles most sodium-ion batteries tend to store about 50% of original capacityCapacity
Capacity is the ability to hold a fluid, very similar to volume.Capacity may also refer to:* Capacity utilization, in economics, the extent to which an enterprise or a nation actually uses its potential output...
. Researchers are now looking at different anode and cathode materials that will allow a sodium cell to maintain its original capacity.
Na/NaxC6
In 1999, D.A. Stevens and J.R. Dahn were the first to test a new anode material made of carbons, (NaxC6). They found the average voltage on the low potential plateau was higher on the Na cells compared to the Li cells. They also showed a glucose precursor can be used to make carbon meterials with a high reversible capacity.NaV1−xCrxPO4F
This type of sodium-ion battery was tested by Haitao Zhuoa, Xianyou Wanga, Anping Tanga, Zhiming Liua, Sergio Gamboab and P.J. Sebastianb. They found that through the reaction:NaF + (1−x)VPO4 + xCrPO4 → NaV1−xCrxPO4F
the introduction of the Cr
Chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
helped the battery retain more energy through cycles of charge and discharge. The chart below (from their study) shows the differences between the battery with and without Cr
Chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
.
| Cathode materials | The first charge capacity (mAh g-1) | The first discharge capacity (mAh g-1) | Capacity loss in the first cycle (mAh g-1) | Reversible efficiency in the first cycle (%) | The discharge capacity at the 20th (mAh g-1) | The capacity retention ratio at the 20th (%) |
|---|---|---|---|---|---|---|
| NaV0.92Cr0.08PO4F | 83.3 | 75.2 | 8.1 | 90.3 | 68.8 | 91.4 |
| NaV0.96Cr0.04PO4F | 93.3 | 82.6 | 10.7 | 88.5 | 67.9 | 82.2 |
| NaVPO4F | 106.9 | 87.7 | 19.2 | 82.0 | 64.5 | 73.5 |
Na2FePO4F
In 2007 researchers B. L. Ellis, W. R. M. Makahnouk, Y. Makimura, K. Toghill, and L. F. Nazar tested Na2FePO4F and Li2FePO4F cathode materials in rechargeable batteries along with a mixtureMixture
In chemistry, a mixture is a material system made up by two or more different substances which are mixed together but are not combined chemically...
of the two cathode materials. They found the sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
cathode easily replaces a lithium
Lithium
Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly...
iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
in a Li cell. The combined lithium-ion and sodium-ion make up would lower the overall price of the battery.