What Is a Nickel-Zinc Battery?

Nickel-zinc (NiZn) batteries are a new type of battery that can replace nickel-metal hydride batteries. They are nominally 1.6V, and there are 5 aa and 7 aaa. Compared with nickel-metal hydride and nickel-cadmium batteries, it has the characteristics of high voltage and strong discharge current. It has unparalleled advantages in digital cameras, flashes, and electric toys.

Chinese name: Ni-Zn battery
Material: Nickel zinc

Voltage: 1.6V
Application: Digital camera, flash

Introduction to Ni-Zn Battery

The nickel-zinc battery has a high voltage. It has a voltage of 1.6V compared to past AA batteries. It is much higher than the 1.2V of Ni-MH batteries, and is more suitable for traditional appliances using 1.5V batteries. It can make the flash recharge faster. Allow the digital camera to run out of power. And many Ni-MH batteries used in digital cameras use only 30% of the power and shut down with low power. (December 2010) The capacity of AA model nickel-zinc battery is only about 1300mAh, but its discharge energy has reached more than 8300 Joules. Compared with eneloop, the best nickel-metal hydride battery at present, the difference is not large, and the discharge energy of eneloop is about 9,000 joules.

Nickel-zinc batteries have strong discharge currents. Already used in electric cars. An AA nickel-zinc battery can discharge more than 7,200 joules of energy under a 2A current discharge. Nickel-zinc batteries are more environmentally friendly, and both nickel and zinc are recyclable and easily recyclable metals.

Nickel-zinc batteries are relatively new products until 2013, and are mainly produced by an American company PowerGenix worldwide, so the price is still relatively high. It is believed that its price can drop to the same level as nickel-metal hydride batteries in the next few years.

Regarding the safe voltage range of nickel-zinc batteries, Volkswagen judges based on its charger's full voltage of 1.9v, and the minimum safe voltage is 1.2v, which is 1.2v ~ 1.9v. In actual use, someone overcharges or overcharges the battery, causing the battery to fail or be damaged. For details, search for "nickel-zinc overdischarge" to see the contributions of volunteers.

Development process of nickel-zinc batteries

Both nickel and zinc are relatively easy to find metals. Compared to nickel-metal hydride batteries, which require a large amount of rare earth materials, nickel-zinc batteries require zinc in addition to nickel, which is easier to find than rare earth. In fact, a century ago, Thomas Edison recognized the potential of nickel-zinc batteries and studied them. Restricted by the technology at the time, nickel-zinc batteries have not been well developed. Today, nickel-cadmium and nickel-metal hydride chemistry (nickel-cadmium batteries and nickel-metal hydride batteries) have been successfully commercialized and are widely used in demanding applications. However, these technologies have reached their technical limits.

At present, our common AA (No. 5) rechargeable batteries, nickel-cadmium batteries, are the least environmentally friendly, have memory effects, and are already on the verge of elimination. Although NiMH batteries do not have memory effects and highly toxic problems, they do have passivation (high self-discharge) and are more demanding on ambient temperature.

In early 2010, a little-known American company PowerGenix announced the launch of a "new" NiZn nickel-zinc rechargeable battery. The reason for quoting new words is that nickel-zinc battery technology actually has a history of more than 100 years, and it is said that it was first invented by Edison. PowerGenix refurbished this ancient technology, especially improved the electrolyte and electrode formulations, and then came up with the new generation of NiZn nickel-zinc rechargeable batteries we saw.

Ni-Zn battery structure

Nickel zinc battery

The main active material of a nickel electrode is Ni (OH) ₂ . Nickel electrodes currently used are mainly classified into sintered and non-sintered types. Non-sintered positive electrode has the characteristics of high capacity and high activity compared with sintered positive electrode. Generally, fiber nickel or foamed nickel material with higher porosity is used as a support, and a spherical nickel hydroxide is coated to obtain a nickel positive electrode.

Nickel zinc battery zinc anode

The main preparation methods of zinc anode include paste method, electrodeposition method, compression method, chemical method and sintering method. The zinc anode can be made into two states of charge and discharge, mainly depending on whether the initial material is ZnO (charged state) or Zn (discharged state). Generally, the Zn electrode in the discharged state is used for the primary battery, and the ZnO in the charged state is mostly used for the secondary battery. However, because ZnO has semiconductor characteristics and poor electrical conductivity, if the zinc anode material of the prepared nickel-zinc secondary battery is all ZnO, it will have a high initial resistance, and its electrodes must be charged and activated with a small current to reduce a certain percentage of ZnO Generate Zn, use the good conductivity of metal zinc Zn to reduce the resistance of the zinc negative electrode, improve the charge and discharge efficiency, and improve the electrochemical performance of the electrode. Therefore, in nickel-zinc secondary batteries, the active material of the zinc anode is mainly ZnO (charged state). Some metal Zn (discharged state) is added to reduce the high resistance during initial charging. At the same time, some corrosion inhibitors are added to improve Performance of zinc anode. Because of the certain solubility of ZnO in alkaline electrolyte, it will cause dendrite deformation and passivation of zinc anode.

Ni-Zn battery separator

The separator is placed between the positive and negative electrodes of the battery to prevent the positive and negative active materials from directly contacting the battery to cause a short circuit. The separator must not only resist zinc dendrite penetration, but also be resistant to strong alkalis, oxidation resistance, easy to be wetted by electrolyte, good mechanical strength and strong flexibility, low resistance and high ionic conductivity.

Nickel-zinc battery electrolyte

The performance of battery anode and cathode materials is directly affected by the type and concentration of the electrolyte. Potassium hydroxide solution is often chosen as the electrolyte by alkaline batteries. The negative electrode active material ZnO is an amphoteric oxide and has a certain solubility in alkaline electrolyte, which directly affects the utilization rate of the zinc negative electrode active material. Therefore, a small amount of LiOH is usually added to the electrolyte. Li is adsorbed on the surface of the active material particles of the positive electrode to avoid agglomeration of the active material particles. The utilization rate of the active material of the electrode is improved. Li can also prevent the electrode from expanding, improve the reversibility of the electrode reaction and the polarization of oxygen evolution during charging, and prolong it. Electrode life. ^[1]