Which battery has the most voltage？Can Lithium battery cells exceed 4.2V？

Which battery has the most voltage？

Battery works on an interesting concept, associated with metals called the electrochemical potential. Electrochemical potential is the tendency of a metal to lose electrons. Base on the concept of electrochemical potential.

A general electrochemical series is shown here. Lithium 3.04V, Mg 2.37V, Al 1.66V, Zn 0.76V, Fe 0.44V, etc. Which battery has the most voltage？ According to these values, Lithium has the highest tendency to lose electrons.

There are lots of possibilities to find materials that could have high Voltage and energy density than Lithium in the future, scientists have high efficiency and advanced ways to find out, as the videos show, maybe in 2 or 3 decades, the highest Voltage would no longer be Lithium, even something like EV or electric airplane would be put into use. In the future, Which battery has the most voltage？ We are not sure yet.

Can Lithium battery cells exceed 4.2V？

Now we know which battery has the most voltage, but what is the most Voltage of Lithium battery could reach?

The voltage of a lithium battery is determined by the electrode potential. Voltage, also known as potential difference, is a physical quantity that measures the energy difference of charges in an electrostatic field due to a difference in potential. The electrode potential of a lithium battery is about 3V, and the voltage varies with different materials. For example, the nominal voltage of an ordinary lithium battery is 3.7V, and the fully charged voltage is 4.2V. The nominal voltage of the lithium iron phosphate battery is 3.2V, and the full charge voltage is 3.65V. In other words, in actual use, the potential difference between the positive and negative electrodes of a lithium battery cannot exceed 4.2V, which is based on the requirements of materials and use safety.

If a Li/Li+ electrode is used as a reference potential, μA is the relative electrochemical potential of the negative electrode material, μC is the relative electrochemical potential of the positive electrode material, Eg is the electrolyte potential range, is the lowest electron unoccupied energy level and the highest electron unoccupied energy level Occupy the energy level. Therefore, the maximum voltage of a Li-ion battery is determined by μA, μC, Eg.

The difference between μA and μC is the open circuit voltage (highest voltage value) of the lithium battery. When the voltage value is within the Eg range, normal operation of the electrolyte can be ensured. Normal operation means that the lithium battery moves back and forth between the positive electrode and the negative electrode through the electrolyte, but does not undergo redox reactions with the electrolyte, thereby ensuring the stability of the battery structure. The electrochemical potential energy of the positive and negative electrode materials causes the electrolyte to work abnormally in two forms:

When the electrochemical potential of the negative electrode is higher than the lowest electron and unoccupied energy level of the electrolyte, the electrons of the negative electrode will be captured by the electrolyte, and the electrolyte will be oxidized, and then the reaction product will form a solid-liquid interface layer on the surface of the negative electrode material particles. As a result, the negative electrode may be damaged.

When the electrochemical potential of the cathode is lower than the highest electron-occupancy energy level of the electrolyte, the electrons in the electrolyte will be captured by the cathode and oxidized by the electrolyte. Then, the reaction product forms a solid-liquid interface layer on the surface of the positive electrode material particles, resulting in possible damage to the positive electrode.

However, the possibility of damaging the positive or negative electrodes is due to the presence of a solid-liquid interfacial layer, which prevents further movement of electrons between the electrolyte and the positive and negative electrodes, and conversely protects the electrode materials. That is, the lighter solid-liquid interface layer is protective. The premise of this protection is that the electrochemical potentials of the positive and negative electrodes can slightly exceed the Eg interval, but not too much. For example, the reason why most current lithium battery anode materials use graphite is that the electrochemical potential of graphite related to Li/Li+ electrodes is about 0.2V, which is slightly higher than the Eg range (1V~4.5V), but due to its protective properties, The solid-liquid interfacial layer prevents further reduction of the electrolyte, thereby preventing the continued development of the polarization reaction. However, 5V high-voltage cathode materials are far beyond the Eg range of current commercial organic electrolytes, and thus are easily oxidized during charge and discharge. As the charging and discharging time increases, the capacity decreases and the service life also decreases.

The reason why the open circuit voltage of the lithium battery is selected is 4.2V, because the Eg range of the electrolyte of the existing commercial lithium battery is 1V～4.5V. The Ovonic editor reminds everyone that if the open circuit voltage is set to 4.5V, the output power of the lithium battery may increase, which will also increase the risk of battery overcharging, and many data have explained the harm of overcharging.

Conclusion

Which battery has the most voltage? In another word, without series and parallel, Lithium batteries have the most voltage at 4.2V today.