Product Name: Lithium Ion Capacitor 3.8V 40F
As a new type of energy storage device, lithium-ion capacitors have the advantages of high power density, high electrostatic capacity and relatively long cycle life, and are expected to be widely used in new energy vehicles, solar energy, wind energy and other fields. Its working principle is different from that of lithium-ion batteries and supercapacitors .
1. The working principle of lithium-ion battery
Lithium-ion batteries are the fastest-growing secondary batteries after nickel-cadmium and nickel-hydrogen batteries. The positive and negative active materials of lithium-ion batteries are compounds that can reversibly intercalate and deintercalate lithium. At least one electrode material is in a lithium intercalation state before assembly, such as transition metal oxide LiCoO 2 as the positive electrode, and various carbon Materials, metal oxides or alloys, etc., are used as negative electrode materials . The working principle of lithium-ion batteries is that graphite is used as the negative electrode and LiCoO 2 is used as the positive electrode. During charging, lithium ions are extracted from the positive electrode material, and migrated to the negative electrode through the electrolyte under the driving of the electrochemical potential gradient. The charge balance requires that the same amount of electrons flow from the positive electrode to the negative electrode under the external circuit, and the lithium ions that obtain electrons are regenerated after reaching the negative electrode. It is embedded into the lattice of the negative electrode material; during discharge, the reverse process is performed, that is, the lithium ions leave the negative electrode lattice and are embedded in the positive electrode to form LiCoO 2 again.
In addition to "oxidation-reduction", the working principle of lithium-ion batteries is also based on electrochemical intercalation-extraction reactions, that is, during the charging and discharging process of lithium-ion batteries, lithium is used as a carrier for energy exchange in the form of ions. The insertion and extraction of the ions swing between the positive and negative electrodes to achieve the purpose of energy exchange. Compared with other batteries, lithium-ion batteries have the advantages of high energy density, high average output voltage, high charging efficiency, low self-discharge efficiency, good safety performance, and long cycle and service life.
2. The working principle of supercapacitors
Supercapacitors are generally mainly composed of electrodes, electrolytes, current collectors and separators.
When charging, the electrons are transferred from the positive electrode to the negative electrode through the external power supply, so that the positive electrode and the negative electrode are respectively positively and negatively charged. At the same time, the positive and negative ions in the electrolyte solution body are separated and moved to the electrode surface to confront the charge layer on the electrode surface to form an electric double layer. ; During discharge, electrons flow from the negative electrode to the positive electrode through the load, positive and negative ions are released from the electrode surface and return to the body of the electrolyte solution, and the electric double layer disappears at the same time. It can be seen that the electric double layer capacitor uses the electric double layer at the interface between the electrode and the electrolyte to store the charge. The charging and discharging process is always a physical process and no electrochemical reaction occurs, so it has stable performance, short charging and discharging time, long cycle life, high power It has the advantages of high density and good high and low temperature performance.
3. The working principle of lithium-ion capacitors
The positive electrode material is an activated carbon material with electric double layer energy storage, the negative electrode material is an intercalated carbon material with lithium ion deintercalation function, and the electrolyte is a lithium salt electrolyte. When the battery is charging, the lithium ions are separated from the surface of the positive electrode material, and inserted into the lattice of the negative electrode material after passing through the electrolyte and the separator; when discharging, the lithium ions are detached from the lattice of the negative electrode material and return to the positive electrode material through the electrolyte. On the surface, an electric double layer is formed with the charge of the positive electrode. The negative electrode potential after lithium insertion is low, and it has the characteristics of high operating voltage, energy density and power density between lithium-ion batteries and supercapacitors.
4. Compared with lithium-ion batteries and lithium-ion capacitors, lithium-ion capacitors
Advantages of supercapacitors
Comparison of capacity, voltage, self-discharge
The energy density of lithium-ion capacitors is lower than that of lithium-ion batteries, but the output density is high; the energy density of single volume is 10~15Wh/L, which is much larger than the capacity of 2~8Wh/L of electric double layer capacitors, which is the latter's energy density. Twice.
In terms of voltage, the voltage of lithium-ion capacitors can reach 4V, which is similar to that of lithium-ion batteries, much higher than that of electric double-layer capacitors, and smaller than both in terms of self-discharge.
Due to the use of lithium oxide, the positive electrode of lithium-ion batteries not only contains a large amount of lithium, which can form lithium dendrites and pierce the separator, but also contains oxygen, an important ignition element. Once the battery is short-circuited, the overall thermal decomposition can develop, and the reaction with the electrolyte can cause combustion. The positive electrode of lithium-ion capacitors is activated carbon, even if the internal short circuit will react with the negative electrode, but it will not react with the electrolyte. In theory, it will be much safer than lithium batteries.
In order to achieve long life, lithium-ion batteries have a certain range of charging and discharging depth limits, which reduces the capacity that can be used in essence. It is difficult to extend the practical life by this alone. However, even if the positive electrode potential of the lithium ion capacitor is lowered, the voltage of the cell itself does not drop significantly, so the capacity can be ensured.
High temperature resistance
Under high temperature conditions, the electrolyte and the positive electrode are prone to oxidative decomposition. For this reason, the potential of the positive electrode may need to be lowered under high temperature conditions. However, when the potential is lowered, the overall voltage of the electric double layer capacitor drops and the capacity cannot be ensured. Lithium-ion batteries, on the other hand, cannot reduce pressure, which is prone to safety problems. Only lithium-ion capacitors can be used in locations where the positive electrode potential is far from the oxidative decomposition region, so they have excellent high-temperature performance.
Product performance table:
Standard capacitance (@25±2℃)
Resistive AC (1KHz, 3.8V)
Pulse (1 second)
1. The operating temperature of lithium-ion capacitors should not exceed the upper or lower limit of the rated temperature (-20 degrees to +55 degrees)
2. Lithium-ion capacitors should be used at nominal voltage. At the same time, in order to prolong the service life of the product, it is recommended that the monomer be used within the range of " rated voltage " (2.5v-3.8v).
3. Please confirm the polarity of lithium-ion capacitors before use, and avoid reverse connection.
4. The external ambient temperature has a heavy impact on the life of lithium-ion capacitors, please keep away from heat sources.
5. Do not directly touch water, oil, acid or alkali for lithium ion capacitors.
6. Do not knead, nail, or disassemble Li-ion capacitors.
7. Do not discard lithium-ion capacitors at will. When discarding, please dispose of them in accordance with national environmental protection standards.
1. During the transportation of lithium-ion capacitors, avoid violent vibration, kneading, rain and chemical corrosion, and handle with care.
2. Lithium-ion capacitors should not be placed in places with a relative humidity of more than 85% or containing toxic gases. In such an environment, the leads and casings are susceptible to moisture and corrosion, resulting in circuit breakers for ultra-fast rechargeable batteries.
3. If the lithium-ion capacitor needs to be stored for a long time, please store it in a place with a temperature of -40~35 degrees, a relative humidity below 50%, and good ventilation.
4. If the lithium-ion capacitor needs to be stored for a long time, please ensure that the product voltage is within the range of 2.5V-3.8V, and the product voltage must not be lower than 2.5V for storage.