The propensity of metals to form irregular and nonplanar electrodeposits at liquid-solid interfaces has emerged as a fundamental barrier to high-energy, rechargeable batteries that use metal anodes. We report an epitaxial mechanism to regulate nucleation, growth, and reversibility of metal anodes. The crystallographic, surface texturing, and electrochemical criteria for reversible epitaxial electrodeposition of metals are defined and their effectiveness demonstrated by using zinc (Zn), a safe, low-cost, and energy-dense battery anode material. Graphene, with a low lattice mismatch for Zn, is shown to be effective in driving deposition of Zn with a locked crystallographic orientation relation. The resultant epitaxial Zn anodes achieve exceptional reversibility over thousands of cycles at moderate and high rates. Reversible electrochemical epitaxy of metals provides a general pathway toward energy-dense batteries with high reversibility.

Operando, spatiotemporal resolved synchrotron X-ray fluorescence mapping measurements on a custom aqueous Zn/α-MnO2 cell provided direct, quantitative evidence of a Mn dissolution-deposition faradaic mechanism that governs the electrochemistry.

A thick electrode with high areal capacity is a straightforward approach to maximize the energy density of batteries, but the development of thick electrodes suffers from both fabrication challenges and electron/ion transport limitations. In this work, a low-tortuosity LiFePO4 (LFP) electrode with ultrahigh loadings of active materials and a highly efficient transport network was constructed by a facile and scalable templated phase inversion method. The instant solidification of polymers during phase inversion enables the fabrication of ultrathick yet robust electrodes. The open and aligned microchannels with interconnected porous walls provide direct and short ion transport pathways, while the encapsulation of active materials in the carbon framework offers a continuous pathway for electron transport. Benefiting from the structural advantages, the ultrathick bilayer LiFePO4 electrodes (up to 1.2 mm) demonstrate marked improvements in rate performance and cycling stability under high areal loadings (up to 100 mg cm–2). Simulation and operando structural characterization also reveal fast transport kinetics. Combined with the scalable fabrication, our proposed strategy presents an effective alternative for designing practical high energy/power density electrodes at low cost.