All solid state battery enter the arena – A new challenger in the field of energy storage

All solid state battery has entered the arena. With the gradual progress of science and technology, people’s requirements for energy storage and conversion have gradually increased. Traditional Lithium ion batteries can no longer meet people’s high requirements for battery energy storage, so a new challenger.

Advantages of all solid state batteries

Traditional lithium ion batteries are mainly composed of positive electrode, negative electrode, separator, electrolyte, structural case, and other components. As the name implies, an all solid state battery contains no gas or liquid in the battery, and all materials exist in solid form. The solid electrolyte is used to replace the liquid components used in existing lithium ion batteries. After using solid electrolytes, all solid state battery can achieve lighter mass, smaller volume, and greater energy density improvement compared to ordinary lithium ion batteries.

1. Compared to commercial lithium ion batteries, the most prominent advantage of all solid state batteries is their safety. Solid state electrolytes are nonflammable, non corrosive, non volatile, and do not have leakage problems, so all solid state battery have inherent safety and longer service life.
2. Solid state batteries are expected to achieve higher energy density. Energy density is the product of specific capacity and battery voltage. Solid state electrolytes generally have a wider electrochemical window than organic electrolytes, which is conducive to further broadening the voltage range of the battery. In the development of large capacity electrodes, solid state electrolytes can prevent the growth of lithium dendrites, thereby fundamentally avoiding the short circuit phenomenon in batteries, making it possible for metal lithium to be used as a negative electrode. For lithium sulfur batteries, solid electrolyte can prevent the migration of polysulfides. For lithium-air batteries, solid electrolytes can prevent oxygen from migrating to the negative electrode side to consume a metal lithium negative electrode.
3.  Solid state battery is expected to achieve higher power density. Solid state electrolytes use lithium ions as a single carrier, without concentration polarization, and can work under high current conditions to improve the power density of the battery.
4. The inherent high and low temperature stability of solid state materials provides a basic guarantee for all solid state batteries to operate in a wider temperature range.
5. Solid state battery also have the characteristics of compact structure, adjustable scale, and large elasticity involved. Solid state batteries can be designed as thin film batteries with a thickness of only a few microns for driving micro electronic devices, or they can be made into macroscopic batteries for driving electric vehicles, power grid energy storage, and other fields. In these applications, the shape of the battery can also be designed according to specific needs.

Solid electrolyte material

For all solid state lithium batteries, especially those that can adapt to future electric vehicles and large-scale energy storage applications, the solid electrolyte used should meet the following requirements.

1.  With high room temperature conductivity (>10-4S/cm).
2. electronic insulation (Li+ migration number is approximately 1).
3. Electrochemical window width (greater than 6V relative to Li+/Li).
4. Good compatibility with electrode materials.
5. Good thermal stability, moisture resistance, and excellent mechanical properties.
6. Easy availability of raw materials, low cost, simple synthesis method.

The investment boom in solid state batteries has arrived

The emergence of solid state batteries has given more possibilities for the development of electric vehicles. Governments and enterprises around the world have also attached importance to such a new battery technology that can achieve a better balance between performance and safety.

Japan: Japan’s New Energy Industry Technology Comprehensive Development Agency (NEDO) announced in 2018 that some enterprises and academic institutions in the country will jointly develop the next generation of electric vehicle solid state lithium batteries within the next five years, striving to be applied to the new energy industry as soon as possible. The project is expected to have a total investment of 10 billion yen. 23 automotive, battery, and material companies, such as Toyota, Honda, Nissan, and Panasonic, as well as 15 academic institutions, such as Kyoto University and the Japanese Institute of Physics and Chemistry, will participate in the research. It is planned to fully master all solid state battery related technologies by 2022.

Germany: German Chancellor Angela Merkel announced in November 2018 that she plans to allocate 1 billion euros to support a battery manufacturer in Germany, and will also fund a battery research and development institution to develop the next generation of solid state batteries. The German government’s move aims to reduce the dependence of German car companies on battery suppliers from China, Japan, and South Korea. Volkswagen and BMW, as German leaders, are also accelerating the development of solid state battery.

United States: The US Department of Energy announced that it would provide incentives for the 2019 fiscal year to car companies engaged in “advanced technology research”. Both General Motors and Ford have received significant research funds. It is reported that the US government has invested a total of US $9.1 million in General Motors, of which US $2 million is explicitly related to the research and development of solid state batteries.

China: China’s research in the field of solid state battery has also started, and the nano pilot project “All Solid State Batteries” led by the Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, has passed the acceptance check; A large number of technology companies and new material companies are conducting research and development of solid state battery.

It can be seen that all solid-state batteries have become the next outlet in the power battery market. Although all solid-state batteries have technical advantages over traditional lithium ion batteries, we must also recognize that this new technology still has many problems, such as the inability to achieve fast charging, high cost, and complex processes. Moreover, there are different technological routes for all solid-state batteries, and it is worth looking forward to taking the lead in achieving marketization.