Carbon coated aluminum foil for decryption

1. Overview of the working principle of lithium batteries and the importance of electrodes

The work of lithium batteries is based on the reversible shuttle of lithium ions between the positive and negative electrodes. During charging, lithium ions escape from the positive electrode, migrate to the negative electrode through the electrolyte and embed in it; In contrast, lithium ions exit from the negative electrode and return to the positive electrode.

As a key component of the negative electrode of lithium battery, hard carbon coated Aluminum Foil electrode plays an extremely important role in the performance optimization of lithium battery by cleverly integrating the excellent electrical conductivity and mechanical stability of aluminum foil with the unique lithium storage performance of hard carbon material.

2, hard carbon coated aluminum foil electrode on the battery energy density enhancement

(1) Contribution of aluminum foil substrate

Aluminum foil has excellent electrical conductivity, and its low resistance ensures that electrons can be transferred quickly and smoothly during the charge and discharge process, reducing the energy loss during the electron transmission process. At the same time, aluminum foil has a high mechanical strength, can provide a solid physical support for the electrode, to prevent the electrode in preparation, winding or lamination and battery use process deformation or damage.

(2) Advantages of hard carbon coating

Compared with traditional graphite anode materials, hard carbon materials have higher theoretical specific capacity. There are abundant micropores and disordered regions in the unique microstructure of hard carbon, which provide more storage sites for lithium ions, so that more lithium ions can be embedded and deembedded during charge and discharge. When hard carbon is uniformly coated on the surface of aluminum foil to form an electrode sheet, the lithium storage capacity of the negative electrode can be significantly increased within a limited volume and mass range.

3, hard carbon coated aluminum foil electrode to improve the battery cycle life

(1) Guarantee of structural stability

In the process of repeated charge and discharge cycles of lithium batteries, the electrode material will inevitably undergo changes in volume expansion and contraction. Because of its special structural characteristics, hard carbon materials have better structural stability than some traditional negative materials. The internal pore structure can effectively buffer the stress generated by lithium ion embedding and deembedding, and reduce the powder and spalling phenomenon of electrode materials caused by volume changes. At the same time, a tight and firm bonding interface is formed between hard carbon and aluminum foil through a carefully designed coating process, which further enhances the integrity of the electrode structure and makes the electrode sheet maintain a relatively stable shape and performance during long-term recycling.

(2) Enhancement of electrochemical stability

The hard carbon material itself has high electrochemical stability, and its chemical structure is not easy to decompose or have adverse reactions with the electrolyte during a long period of charge and discharge. This helps to maintain the stability of the electrochemical environment inside the battery and reduce the deterioration of battery performance caused by changes in the electrode material itself. For example, in some energy storage power station applications, lithium batteries need to go through thousands or even tens of thousands of charge and discharge cycles, and the good cycle stability of hard carbon coated aluminum foil electrodes can ensure that the battery always maintains a high capacity retention rate and charge and discharge efficiency during long-term use, which greatly reduces the maintenance cost and replacement frequency of the energy storage system. The economy and reliability of the whole energy storage system are improved.

4, the positive impact of hard carbon coated aluminum foil electrode on the battery rate performance

(1) Lithium ion fast transmission channel

The structure design of the hard carbon coated aluminum foil electrode provides a fast transmission channel for lithium ions. The high conductivity of aluminum foil provides a high-speed path for electron conduction, while the microstructure characteristics of hard carbon materials, such as suitable pore size distribution and short lithium ion diffusion path, allow lithium ions to spread and migrate quickly inside the electrode.

(2) Reduce charge transfer resistance

The hard carbon coated aluminum foil electrode can reduce the charge transfer resistance between electrode and electrolyte by optimizing the material composition and structural design. When the charge transfer resistance is reduced, the transfer speed of lithium ions at the electrode/electrolyte interface is accelerated during charge and discharge, and the combination and separation process of electrons and ions is more efficient.

5, hard carbon coated aluminum foil electrode to ensure the safety of the battery

(1) Advantages of thermal stability

During the use of lithium batteries, especially in some extreme environmental conditions or abnormal charging and discharging conditions, such as high temperature environment or overcharge and overdischarge, the temperature inside the battery will rise rapidly, which may cause serious safety problems such as thermal runaway. Hard carbon materials have high thermal stability, which is not easy to decompose under high temperature environment, and can effectively inhibit a series of chain reactions caused by rising temperature inside the battery.