Control of Dendritic Growth of the Lithium Metal in All-Solid-State Lithium Metal Batteries: Effect of the Current Collector with Microsized Pores

The dendritic growth of the Li metal through a separator is a serious issue for the development of rechargeable Li metal batteries in which the Li metal is used as the negative electrode. Several methods have been investigated for this issue; however, it has not been completely solved until now. The all-solid-state battery (ASSB) system is one of the most powerful methods for practical use of the Li metal negative electrode because the solid-state electrolyte (SSE) can mechanically block the dendritic growth of Li metal. ASSBs are pressed for reducing interfacial resistance between electrode active materials and SSE; therefore, the high mechanical strength of SSE results in the growth of Li metal through voids among SSE particles, leading to internal short circuit. In this study, a negative electrode current collector with microsized pores where the Li metal could be preferentially deposited was designed and prepared by coating Au or Ni on a commercially available membrane filter with 8 mu m diameter pores. The Li metal deposition/dissolution behavior in the pores of the Au- or Ni-coated membrane filter under galvanostatic conditions was discussed based on scanning electron microscopy images. Consequently, the Li metal deposition occurred in the pores during charging and the deposited Li dissolved from the pores during discharging. Moreover, it was found that there were two modes in the Li deposition in the pores, and the deposition modes could be controlled by coating material and current density.