All-solid-state batteries using inorganic solid electrolytes are considered promising energy storage systems because of their safety and long life. Stackable and compact sheet-type all-solid-state batteries are urgently needed for industrial applications such as smart grids and electric vehicles. A binder is usually indispensable to the construction of sheet-type batteries; however, it can decrease the power and cycle performance of the battery. Here we report the first fabrication of a binder-free sheet-type battery. The key to this development is the use of volatile poly(propylene carbonate)-based binders; used to fabricate electrodes, solid electrolyte sheets, and a stacked three-layered sheet, these binders can also be removed by heat treatment. Binder removal leads to enhanced rate capability, excellent cycle stability, and a 2.6-fold increase in the cell-based-energy-density over previously reported sheet-type batteries. This achievement is the first step towards realizing sheet-type batteries with high energy and power density.

No abstract

The development of a fabrication process for sheet-type all-solid-state batteries with high energy density is critical for industrial applications. In this study, we systematically investigate the fabrication process of cells using composite positive electrode sheets with a high ratio of active materials. n-Decane was selected as a suitable solvent for the slurry because it has a sufficiently low vapor pressure and does not affect the ionic conductivity of solid electrolytes. In addition, the pre-densification of the composite positive electrode sheets was found to be effective in improving the cell performance. Suitable fabrication pressures were also determined. The cells fabricated under low-pressure conditions exhibited higher discharge capacities despite the higher internal resistance. Finally, our study revealed that the fracturing of LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM) occurs under high-pressure fabrication conditions because of the compression between the closely located NCM particles, resulting in the cleavage of the ionic and electronic conduction pathways.

No abstract

No abstract

No abstract