Controlling electrode growth: Batteries with metal anodes can grow dendrites during cycling, which can cause short circuits in a battery or subsequently reduce the charge capacity. Zheng et al. developed a process to electrodeposit zinc on a graphene-coated stainless-steel electrode, such that the zinc forms plates with preferential orientation parallel to the electrode. This is achieved by depositing a graphene layer on stainless steel designed to epitaxially match the basal (002) plane of metallic zinc, minimizing lattice strain. During cycling, the zinc will redeposit in plate form rather than as a dendrite such that the batteries show excellent reversibility over thousands of cycles. Science , this issue p. 645

Scalable approaches for precisely manipulating the growth of crystals are of broad-based science and technological interest. New research interests have reemerged in a subgroup of these phenomena—electrochemical growth of metals in battery anodes. In this Review, the geometry of the building blocks and their mode of assembly are defined as key descriptors to categorize deposition morphologies. To control Zn electrodeposit morphology, we consider fundamental electrokinetic principles and the associated critical issues. It is found that the solid-electrolyte interphase (SEI) formed on Zn has a similarly strong influence as for alkali metals at low current regimes, characterized by a moss-like morphology. Another key conclusion is that the unique crystal structure of Zn, featuring high anisotropy facets resulting from the hexagonal close-packed lattice with a c/a ratio of 1.85, imposes predominant influences on its growth. In our view, precisely regulating the SEI and the crystallographic features of the Zn offers exciting opportunities that will drive transformative progress.

Metals use a chemotaxis-like process to overcome diffusion limitations and prevent dendritic electrodeposition in batteries.

Lithium metal is a promising anode for energy-dense batteries but is hindered by poor reversibility caused by continuous chemical and electrochemical degradation. Here we find that by increasing the Li plating capacity to high values (e.g., 10–50 mAh cm⁻²), Li deposits undergo a morphological transition to produce dense structures, composed of large grains with dominantly (110)_Li crystallographic facets. The resultant Li metal electrodes manifest fast kinetics for lithium stripping/plating processes with higher exchange current density, but simultaneously exhibit elevated electrochemical stability towards the electrolyte. Detailed analysis of these findings reveal that parasitic electrochemical reactions are the major reason for poor Li reversibility, and that the degradation rate from parasitic electroreduction of electrolyte components is about an order of magnitude faster than from chemical reactions. The high-capacity Li electrodes provide a straightforward strategy for interrogating the solid electrolyte interphase (SEI) on Li —with unprecedented, high signal to noise. We find that an inorganic rich SEI is formed and is primarily concentrated around the edges of lithium particles. Our findings provide straightforward, but powerful approaches for enhancing the reversibility of Li and for fundamental studies of the interphases formed in liquid and solid-state electrolytes using readily accessible analytical tools.