The solid electrolyte interphase (SEI) layer is one of the key factors for Li metal anode affecting the Li-deposition behavior and electrochemical performances. However, the fabrication of artificial SEI layers with precisely controlled composition, thickness, and mechanical properties is still challenging and difficult to be realized. In this study, we demonstrate an SEI-inspired dual protective layer for Li metal anode with highly controllable structures and robust mechanical properties (the organic alucone as the outer layer and inorganic Al 2 O 3 as the inner layer), which is deposited by atomic layer deposition (ALD) and molecular layer deposition (MLD) techniques. The dual-layer protected Li anode displays significantly enhanced electrochemical performances, suppressed mossy/dead Li formation, and robust properties during the plating/stripping process. It is believed that our design of dual-layer protected Li metal anode by ALD and MLD opens up new opportunities for the realization of next-generation high-energy-density Li metal batteries.

Graphene has been integrated in many heterogeneous structures in order to take advantage of its superior mechanical properties. However, the complex mechanical response of heterogeneous films incorporating graphene is not well understood. Here, we studied the mechanical behavior of atomic layer deposition (ALD) synthesized TiO/graphene, as a representative building block of a typical composite, to understand the mechanical behavior of heterostructures using an experiment-computational approach. The inclusion of graphene was found to significantly enhance the Young's modulus of TiO/graphene hetero-films for films below a critical thickness of 3 nm, beyond which the Young's modulus approaches that of pure TiO film. A rule-of-mixtures was found to reasonably estimate the modulus of the TiO/graphene hetero-film. Experimentally, these hetero-films were observed to fail via brittle fracture. Complimentary density functional theory and finite element modeling demonstrates strong adhesion at the graphene TiO interface and that graphene serves as a reinforcement, providing the hetero-film with an ability to sustain significantly high stresses at the point of failure initiation. The results and methodology described herein can contribute to the rational design of strong and reliable ultrathin hetero-films for versatile applications.

Lithium metal is regarded as the “Holy Grail” of anode materials due to its low electrochemical potential and high theoretical capacity. Unfortunately, its unstable solid electrolyte interphase (SEI) leads to low Coulombic efficiency (CE) and serious safety issues. Herein, a hybrid nanoscale polymeric protective film with tunable composition and improved stiffness is developed by incorporating aluminum crosslinkers into the polymer chains. The Li plating/stripping process is regulated through the protective coating and the dendrite growth is effectively suppressed. Promisingly, the protected Li can deliver stable performance for more than 350 h with a cycling capacity of 2 mAh cm−2 without a notable increase in overpotential. Moreover, a stable charge/discharge cycling in Li–O2 batteries with the protected Li can be maintained for more than 600 h. This work provides guidance on the rational design of electrode interfaces and opens up new opportunities for the fabrication of next‐generation energy storage systems.