Solid-state batteries are a type of battery technology. Unlike the commonly used lithium-ion and lithium-ion polymer batteries, solid-state batteries use solid electrodes and solid electrolytes.
Since the scientific community believes that lithium-ion batteries have reached their limits, solid-state batteries have been regarded in recent years as a battery that can succeed lithium-ion batteries.
Solid-state lithium battery technology uses glass compounds made of lithium, sodium, etc. as the conductive material, replacing the electrolyte of traditional lithium batteries, which greatly improves the energy density of lithium batteries, making it twice the energy density of lithium-ion batteries.
The market expects that solid-state battery technology will make breakthrough progress in 2021, further catching up with lithium-ion battery technology in terms of cost, energy density and production process.
By 2030, solid-state batteries will be the mainstream battery for electric vehicles, and lithium-ion batteries will no longer be the mainstream battery for electric vehicles, but lithium-ion batteries will still have a place in some electronic component fields.
Compared to traditional lithium-ion batteries, solid-state batteries have four major advantages.
One advantage is its light weight. The use of a fully solid-state electrolyte changes the applicable material system for lithium-ion batteries. A key aspect of this is that it eliminates the need for lithium-intercalated graphite anodes; instead, metallic lithium can be used directly as the anode. This significantly reduces the amount of anode material used, resulting in a substantial increase in the overall battery energy density.
The second advantage is its thinness. Traditional lithium-ion batteries require separators and electrolytes, which together account for nearly 40% of the battery's volume and 25% of its mass. However, if these are replaced with solid-state electrolytes (mainly organic and inorganic ceramic materials), the distance between the positive and negative electrodes (traditionally filled by separators and electrolytes, now filled by solid-state electrolytes) can be shortened to only a few to a dozen micrometers. This significantly reduces the battery's thickness—therefore, all-solid-state battery technology is an essential path to battery miniaturization and thin-film technology.
The third advantage is the prospect of flexibility. Even brittle ceramic materials can often be bent when their thickness is reduced to below the millimeter level, making the material flexible. Correspondingly, the flexibility of all-solid-state batteries will also be significantly improved after they become thinner and lighter. By using appropriate encapsulation materials (not rigid shells), the batteries can withstand hundreds to thousands of bends while maintaining essentially no performance degradation.
The fourth advantage is greater safety. Traditional lithium batteries may pose the following dangers: (1) Lithium dendrites may form when operating under high current, which may puncture the separator and cause short circuit damage; (2) The electrolyte is an organic liquid, which is prone to side reactions, oxidation decomposition, gas generation, and combustion at high temperatures. By adopting all-solid-state battery technology, the above two problems can be directly solved.
However, although solid-state batteries will realize the transformation of all-solid electrolyte and lithium metal anode, issues such as conductivity, safety, stability and high cost still need to be solved.
In general, as solid-state battery technology gradually develops, companies in fields such as high-nickel cathodes, lithium carbonate, and silicon-carbon anodes will have new opportunities due to solid-state batteries, while electrolyte and separator companies will be impacted.
