Japan Develops All-Solid-State Batteries Made Without Vacuum, Reducing Costs

Shintaro Yasui, an assistant professor at Tokyo Institute of Technology in Japan, and others have developed an all-solid-state battery that can be manufactured by simply applying an electrolyte and letting it dry in air.best lithium ion battery machine company Currently, all-solid-state batteries, which are already under development, need to be manufactured in a vacuum using a special device because the electrolyte is not resistant to moisture. The new all-solid-state battery developed by Tohoku University can easily reduce manufacturing costs. The R&D team believes that it will be beneficial to reduce costs and is striving for practical realization.

Electrolyte that can be manufactured by coating

All-solid-state batteries are batteries that change the electrolyte of current lithium-ion batteries from liquid to solid. Since the electrolyte does not use flammable organic solvents, safety is improved. In addition,equipment for lithium battery assembly the ionic conductivity of the electrolyte is higher than that of the liquid electrolyte, which has the advantage of increasing storage capacity.

However, the electrode materials of all-solid-state batteries are prone to expansion and contraction. This can directly lead to fracture of the part connected to the electrolyte, the ionic conductivity decreases, and the battery life can be shortened.

In addition, the sulfide electrolyte, which is expected to be the electrolyte for on-board all-solid-state batteries, is prone to decomposition due to moisture. It becomes unstable in air and needs to be manufactured in a vacuum. According to the findings of the Japan Science and Technology Agency (JSTA), the cost of equipment required for manufacturing is 10 ~ 20 times higher than that of existing lithium-ion batteries. Manufacturing costs need to be cut.

In this context, the research team explored solid electrolytes, which can be manufactured without special equipment, applied, or dried. At the heart of a solid electrolyte is a compound of lithium, boron and oxygen. This compound is pulverized in a special way and surrounded by non-volatile, non-flammable lithium salts and water to form a liquid called a slurry.

The anode and solid electrolyte are sequentially coated on the collector fluid, and the cathode and solid electrolyte are coated on another collector fluid. They are allowed to dry naturally in air separately. The electrolyte enters the periphery of the positive and negative materials, and the electrodes are tightly bonded to the electrolyte. The collectors were overlapped and sealed with a film, and a pressure of about 30 MPa was applied at room temperature and the performance of the cell was measured.

The ionic conductivity value for the cell performance was 5.9 msw/cm. a relatively high value can be obtained among all solid-state battery electrolytes. It can withstand about 300 charges and discharges and "is expected to reach 1,000," says Anai.

However, around 140 degrees Celsius we have a potential for damage and possibly poor temperature change characteristics. It is currently driven at about 2.4V, and faces the subject of how to use it at higher voltages as an option.

All-solid-state batteries are becoming a reality, including efforts by automakers around 2020. This solid-state electrolyte is also expected to improve its performance through improved electrodes and processes.