Development of next-generation high-energy lithium (Li) metal batteries is hindered by uncontrollable growth of Li dendrites and the unstable Li/electrolyte interface during repeated Li plating/stripping.

Uncontrolled growth of dendrites in lithium metal batteries (LMBs) permeate into the separator and reach the cathode, causing internal short circuit and eventually leading to serious safety accidents. Herein, we...

Uncontrolled lithium (Li) plating/stripping is one of the most fatal problems of lithium metal batteries (LMBs). Herein, we modified a copper (Cu) foil current collector surface with an indium nitride (InN) thin film, which regulated the Li plating/stripping process through in situ lithiation. That is, InN transformed into a lithium nitride (Li3N)/Li–In alloy phase (Li x In y )-mixed protection layer during the first Li plating process. Li3N is an efficient Li+ conductor and is stable to Li, whereas Li x In y possesses fast Li+ diffusion kinetics. The synergistic effect of these two species simultaneously caused the mixed protective layer to display fast Li+ diffusion, inhibited the rapid growth of Li dendrites, and induced bottom Li deposition under the protective layer. Li∥Cu cells exhibited higher Coulombic efficiency and a more stable lithium plating/stripping process than a control cell without an InN layer. Moreover, when an InN thin film was transplanted onto the surface of a Li metal sheet using the same method, the resulting Li∥Li symmetrical cell delivered extraordinary performance. This in situ formation of a multifunctional modified layer by a facile preparation process could be an effective way to inhibit dendrite growth and accelerate the application of LMBs.

Lithium metal, with a high theoretical capacity of 3860 mAh/g and a low electrochemical potential of À 3.040 V, is an attractive anode material. However, its application has been hampered by irregular lithium dendrite growth and low coulombic efficiency. To solve these problems, a facile air calcination strategy was used to prepare cake-like TiO 2 nanoparticles with rich pores, which were further coated on one side of the commercial Celgard separator. The nanoscale mesoporous channels on the surface of TiO 2 particles can effectively block the growth of lithium dendrites, leading to dense and uniform Li deposition with a high coulombic efficiency. Compared with the blank cell (50 cycles of normal operation), the Li j j Cu cell with modified separator can run 100 cycles at 2 mA/cm 2 with an average coulombic efficiency of 97.3 %. These results herald a new approach to dendrite-free lithium anodes by nanostructured ceramic coating on the separator.