Lithium-ion batteries are commonly known as 'lithium batteriesPreviously, the electrolytes of lithium-ion batteries were all liquid, which also caused the lithium batteries to be prone to explosions and other hazards under harsh conditions such as high temperature and exposure. The emergence of all-solid-state thin-film lithium batteries is expected to bid farewell to 'willful' electrolytes and eliminate battery safety hazards. At present, there are many places where lithium batteries are used. In addition to electronic products such as mobile phones, iPads, cameras, laptops, etc., which are not separated from the body, fashionable and environmentally friendly electric vehicles, and the start of aero engines, all need its help to 'move'. Lithium-ion batteries play an important role in our lives. If one day, lithium batteries choose to 'strike' collectively, perhaps we will have all kinds of uncomfortable things like smoking addiction. Although the possibility of a collective 'strike' is unlikely, if it is used improperly, the organic electrolyte inside the lithium battery occasionally 'tanks' and may cause a safety accident. In the history of aviation, there have been accidents of lithium batteries catching fire in airplane cargo warehouses, which was mainly caused by electrolyte leakage caused by changes in air pressure. When the aircraft flies at an altitude of 10,000 meters, there is only 0.1 atmosphere in the cargo warehouse (1 atmosphere on the ground), which makes the pressure difference between the inside and outside of the lithium battery too large, prone to battery shell breakage, electrolyte leakage, and even spontaneous combustion. In January 2013, the Boeing 787 passenger plane caught fire due to the leakage of electrolyte from the main battery and auxiliary battery. This aircraft, known as the 'safest aircraft. This is why lithium batteries need to be carried with you when you take an airplane (the cabin will be pressurized). How to eliminate the safety hazards of lithium batteries? All-solid-state thin-film lithium batteries may be a good choice to solve existing problems. It is understood that all solid-state lithium-ion batteries are divided into three types: polymer type, sulfide type, and film type according to the type of electrolyte. This article mainly introduces thin-film all-solid-state lithium batteries. The working principle of the all-solid thin-film lithium battery is the same as that of the existing lithium battery. The main difference is that there is no organic electrolyte in the battery. Instead, a solid thin-film electrolyte like paper is used to completely solve the safety hazard of electrolyte leakage. The thin-film lithium battery is mainly composed of a solid substrate and a solid functional thin film layer on the surface of the substrate. The functional thin film layer includes a current collector, a positive electrode, an electrolyte, a negative electrode and a packaging protective film, and the thickness is only 10 μm. The all-solid-state lithium battery is not only safer than traditional lithium batteries, but also has other advantages. For example: (1) High energy density, good rate performance, lower self-discharge rate, longer charge-discharge cycle life, up to 45,000 times, and preserve 95% of the initial capacity. Ordinary lithium batteries generally drop to 80% of their initial capacity after 1,000 cycles. (2) It can be used in more harsh environments, such as stronger resistance to high and low temperature, and good performance at low temperature of -40℃ and high temperature of 150℃, which can be used for high temperature detectors in the semiconductor industry, petroleum exploration and space detection . (3) The electric potential of the film electrode is uniform, and the risk of local overcharge and overdischarge of the electrode is small. (4) The battery can be designed better. The advent of all-solid-state thin-film lithium batteries will allow lithium batteries to bid farewell to the 'willful' electrolyte, thereby bringing users higher safety and a more perfect experience.