Analysis of the Advantages of All-Solid Lithium Battery

In recent years, many automakers have revealed plans to build electric cars based on solid-state batteries. For example, "Fisker applied for a patent for a solid-state lithium battery, with a maximum life of 800km and a charge of 1 minute", "Volkswagen plans to develop a 1000km solid-state battery" and other news are common. What is the power of solid-state batteries? How far is it from practical application? Let's talk more specifically about the status and prospects of solid-state batteries.

What are the advantages of solid state batteries

At present, the global competition for power cells is increasingly fierce. Although Chinese companies have occupied the advantage of market scale in this round of competition, companies such as Europe, the United States, Japan and South Korea are already making arrangements for the next stage and are potential powerful competitors. Many experts called for suggestions that attention should be paid to the development of solid batteries. Although solid state batteries are still in the experimental stage, there is still a certain period of time before industrialization. However, in order to seize the commanding heights of future development, companies have been quick to develop solid-state batteries, and market demand or promote the production of solid-state batteries in advance.

According to the technical goals set in "Made in China 2025", the energy density of lithium batteries will reach 300 Wh/kg in 2020, 400 Wh/kg in 2025, and 500 Wh/kg in 2030. However, based on high-nickel ternary + silica negative electrode materials, the energy density of the existing lithium battery is difficult to exceed 300 W/kg. The energy density of solid-state lithium batteries is about 2.5 to 3 times that of traditional lithium batteries, and it eliminates the potential burning hazards such as battery rupture or high temperature.

The all-solid lithium battery has a very high safety. Its solid electrolyte is non-flammable, non-corrosive, non-volatile, and leaky. At the same time, it also overcomes the phenomenon of lithium dendrite. The self-ignition probability of a car equipped with a full-solid lithium battery will be greatly reduced..

Electrolyte materials are the core of all-solid lithium battery technology. At present, the research on solid electrolytes is mainly concentrated in three major types of materials: polymers, oxides, and sulphides. The polymer has good high temperature performance and has been commercialized. Oxide cycle has good performance and is suitable for thin film flexible structure; The sulphide has the highest conductivity and is the main direction in the future.

Since solid state batteries have so many advantages, why not promote them? This is because solid electrolytes have high resistance and there are still some problems to be solved in terms of power density. It is necessary to start with solid electrolytes and positive and negative electrode materials. There are many challenges in conductivity, battery doubling, battery manufacturing efficiency and cost control. Once these problems can be effectively solved, a new battery revolution will surely be launched in the future.

In the overall development of solid-state batteries, electrolytes may follow the path from liquid, semi-solid, solid to solid, and finally to solid. The author believes that the use of high nickel positive electrode + quasi-solid electrolyte + Silicon carbon negative electrode to achieve 300 Wh / Kg by 2020, and the use of lithium-rich positive electrode + all-solid electrolyte + silicon-lithium metal negative battery to achieve 400 Wh / Kg by 2025, Fuel/Lithium/Air Cell achieved 500 W/Kg by 2030.

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