Solid state battery vs semi-solid state battery vs liquid battery

With the increasing demand for energy, new battery technologies are also emerging. Liquid battery, semi-solid battery, solid-state battery are one of the most common types.

This paper will give a comprehensive overview to these batteries and introduce materials, structure, performance of solid state battery vs semi-solid state battery vs liquid battery in order to better grasp the latest progress of battery technology.

The introduction of liquid battery

The liquid battery is one of the earliest battery types, and its interior is composed of a positive electrode, a negative electrode, battery electrolyte and separator. In liquid batteries, the electrolyte acts as a transfer of ions, allowing charge to flow between the positive and negative electrodes.

Liquid batteries have the following advantages:

? Large battery capacity, high lithium battery energy density.

? Low battery maintenance cost.

However, there are also the following disadvantages:

? Easy to leak, security risks.

? Environmental protection is not good, electrolyte contains harmful substances.

? Life is short and electrolytes need to be replaced frequently.

Liquid batteries are mainly used in automobiles, ships and other large power equipment, as well as in the military field.

The introduction of semi-solid battery

Semi solid battery is a new battery technology between liquid battery and solid battery. A polymer material with a microporous structure is used inside the semi-solid battery instead of the traditional electrolyte, so that positive and negative ions can be transferred through the polymer. Semi-solid batteries have the following advantages:

? High safety, not easy to leak.

? Good environmental protection, the material can be recycled.

? Long batetry life cycle.

However, there are also the following disadvantages:

? Battery capacity is relatively small.

? The flow resistance is large, resulting in a slow loading speed.

Semi-solid state batteries are mainly used in smart wearables, mobile power and other small electronic devices.

The introduction of solid state battery

Solid-state battery is one of the most popular new battery technologies in recent years, and its internal solid electrolyte replaces the traditional liquid electrolyte. Therefore, solid-state batteries have the following advantages:

? High safety, not easy to leak and explode.

? High energy density, high charge and discharge efficiency.

? Can work at lower temperatures.

However, there are also the following disadvantages:

? The production process is complex and costly.

? Maintenance is difficult, and the damaged battery cannot be repaired.

Solid state batteries are one of the most widely used new battery technologies, mainly used in consumer electronics such as smartphones and laptops.

Structure comparison: solid state battery vs semi-solid state battery vs liquid battery

The structure comparison of solid state battery vs semi-solid state battery vs liquid battery are as follows:

Liquid battery

Electrolytes are one of the key materials in liquid batteries. The electrolyte conducts ions between the positive and negative electrode materials inside the battery.

It guarantees the effectiveness of the internal circuit, plays a key role in energy density, power density, cycle life, and safety performance, and is known as the “blood” of the battery. Technology is provided by the top 10 domestic lithium-ion battery electrolyte companies, and China has been quite mature.

Semi-solid state battery

The battery retains part of the electrolyte and separator structure. Semi-solid batteries need to retain a small amount of electrolyte next to the solid electrolyte to improve conductivity, so a separator is needed to separate the positive and negative electrodes. Depending on the technology, solid electrolytes also come in granular and film form.

Solid state battery

Without electrolyte residue, the separator needs to be studied. In a solid state battery, the electrolyte will be completely replaced by a solid electrolyte. Whether to replace the separator depends on different technical routes. In some solid-state battery technology solutions, the separator is retained as the support electrode architecture; In other cases, the diaphragm is completely eliminated.

Comparison of battery materials: solid- state battery vs semi-solid state battery vs liquid battery

The battery materials of solid state battery vs semi-solid state battery vs liquid battery are as follows:

Liquid battery

The liquid battery is composed of four key materials: positive electrode material, negative electrode material, separator and electrolyte, and the cost accounts for 45%, 15%, 18% and 10%, respectively. The main component of the liquid electrolyte is an organic solvent, which dissolves lithium salts and provides a carrier for lithium ions.

Semi-solid state battery

The material used is basically the same as the liquid battery. The semi-solid lithium battery uses a gel electrolyte, takes a polymer as the electrolyte “base film”, adds lithium salt, adds a low molecular organic solvent, and gets a substance with ionic conductivity between a solid electrolyte and a liquid electrolyte through immersion activation.

Solid state battery

As far as solid-state lithium batteries are concerned, the positive electrode material can continue the positive electrode material of lithium-ion batteries, and the negative electrode material is lithium metal without separator. At present, there are four main research areas: lithium sulfide battery, lithium oxide battery, lithium oxide battery, lithium composite electrolyte battery.

Comparison of battery performance: solid state battery vs semi-solid state battery vs liquid battery

Solid state battery vs semi-solid state battery vs liquid battery differ in battery performance in the following ways：

Energy density

It is reported that the highest energy density of liquid batteries is 300Wh/kg. The semi-solid battery is reported to be 360wh/kg, and the energy density will be further improved by improving the positive and negative electrode materials. The current energy density of solid state batteries is 400Wh/kg and is expected to reach 900Wh/kg.

Security

Solid-state battery safety is the best, because there is no flammable liquid electrolyte, no burning, no leakage, no corrosion, semi-solid battery in the middle, liquid battery is the worst.

High and low temperature performance

Solid-state batteries have the best high temperature performance and the worst low temperature performance. Liquid batteries have the best low temperature performance and the worst high temperature performance.

Battery life

Solid-state batteries have a longer service life because they do not have problems such as corrosion and leakage. Semi-solid batteries are in the middle. Liquid batteries have room for improvement in extending battery life.

Sum up

Solid-state batteries support battery film designs as small as a few nanometers, broadening the range of lithium-ion battery applications and making battery independence and flexibility possible.

Due to their safety and potentially high energy density, solid-state batteries are considered an important development direction for the next generation of power batteries.