Lithium-ion batteries are widely used as power storage devices, and on-demand manufacturing technology is required to meet the needs of large-scale power supplies, small-sized power supplies, flexible devices, etc., as the market scale expands and diversifies in the future.However, with regard to 3D printing, which is attracting attention as an on-demand processing technology, it has been difficult to manufacture solid-state lithium-ion batteries at room temperature.

　On the other hand, this research group mixed lithium-ion conductive ionic liquids with flame-retardant, flame-retardant, and low melting point (liquid at room temperature) with oxide nanoparticles to make them solid (pseudo-solid). We have been developing a "pseudo-solid-state lithium-ion battery" that has the same high safety as an all-solid-state battery by using the above as an electrolyte.In this research, we also found that by mixing a pseudo-solid electrolyte material with a resin that cures with ultraviolet rays, 3D printing by stereolithography becomes possible.

　Using this electrolyte ink material and positive and negative electrode ink materials, we succeeded in producing a pseudo-solid lithium-ion battery only by 3D printing.It was demonstrated that the manufactured battery can be stably charged and discharged 100 times or more.

　With the technology developed this time, lithium-ion batteries can be 3D printed at room temperature in a few minutes, so it is possible to directly print on soft materials that are sensitive to heat, such as polymers, and any size can be used depending on the design of the 3D printer. Now, solid lithium-ion batteries of any shape can be manufactured on demand.It is expected to be applied to a wide range of needs for solid-state lithium-ion batteries, from in-vehicle power supplies to wearable devices.

Paper information:[Dalton Transactions] A photo-curable gel electrolyte ink for 3D-printable quasi-solid-state lithiumion batteries