Solid-state
batteries based on a metallic Li anode and nonflammable
solid electrolytes (SEs) are anticipated to achieve high energy and
power densities with absolute safety. In particular, cubic garnet-type
Nb-doped Li7La3Zr2O12 (Nb-LLZO)
SEs possess superior ionic conductivity, are feasible to prepare under
ambient conditions, have strong thermal stability, and are of low
cost. However, the interfacial compatibility with Li metal and Li
dendrite hazards still hinder the applications of Nb-LLZO. Herein,
a quick and efficient solution was applied to address this issue,
generating a nano-Li3PO4 pre-reduction layer
from the reaction of H3PO4 with the ion-exchanged
passivation layer (Li2CO3/LiOH) on the surface
of Nb-LLZO. A lithiophilic, electrically insulating interlayer is
in situ created when the Li3PO4 modified layer
interacts with molten Li, successfully preventing the reduction of
Nb5+. The interlayer, which mostly consists of Li3P and Li3PO4, also has a high shear modulus
and relatively high Li+ conductivity, which effectively
inhibit the growth of Li dendrites. The Li|Li3PO4|Nb-LLZO|Li3PO4|Li symmetric cells stably cycled
for over 5000 h at 0.05 mA cm–2 and over 1000 h
at a high rate of 0.15 mA cm–2 without any short
circuits. The LiFePO4 and S/C hybrid solid-state batteries
using the modified Nb-LLZO electrolyte also demonstrated good electrochemical
performances, confirming the practical application of this interfacial
engineering in various solid-state battery systems. This work offers
an efficient solution to the instability issue between the Nb-LLZO
SE and metallic Li anode.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.