Energy storage devices using electrochemical reactions have become an integral part of our daily lives, and further improvement of their performance is highly demanded. An important task for this purpose is to thoroughly understand the electrochemical processes governing their chemistry. Here we develop a method based on Kelvin probe force microscopy that enables dynamic visualization of changes in the internal potential distribution in an operating electrochemical device and use it to characterize an all-solid-state lithium ion battery. Observation of the cathode composite regions during a cyclic voltammetry operation reveals differences between the behavior of local electrochemical reactions in the charge and discharge processes. Based on careful inspection of the results, we show that the difference arises from a change in the state of an electronic conductive path network in the composite electrode. Our method provides new insights into the local electrochemical reactions during electrochemical operation of devices.

Two-dimensional (2D) boron monosulfide (BS) nanosheets are predicted to have several stable phases and unique electronic structures, endowing them with interesting attributes, including superconducting, thermoelectric, and hydrogen storage properties. In...

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Realization of lithium-metal (Li) batteries is plagued by the dendritic deposition of Li leading to internal short-circuit and low Coulombic efficiency. The Li-deposition process largely depends on the liquid electrolyte that reacts with the Li metal and forms a solid electrolyte interphase (SEI) layer with diverse chemical and physical properties. Moreover, the electrolyte possesses characteristic ion transport behaviors and directly affects the deposition kinetics at the electrode surface. As a result, the convolution of interfacial, ion transport, and kinetic effects of an electrolyte obscures the understanding of Li deposition in Limetal batteries. Herein, the dynamic processes and the interfacial properties of Limetal electrodes are precisely delineated in representative ether electrolytes. It is found that a combination of homogeneous SEI and slow deposition kinetics produces layer-by-layer epitaxial growth of Li. In contrast, the dendritic growth of Li is observed when the SEI is inhomogeneous and the reaction rate is fast. Nevertheless, it is shown that a homogeneous SEI is not a prerequisite in suppressing Li dendrites when the adverse effect of an unfavorable SEI can be subdued by proper kinetic tuning at the interface. Furthermore, an otherwise kinetically unstable electrolyte can also be made compatible with the Li-metal electrode when covered with a properly designed SEI. This delineation of the roles of SEI and deposition kinetics gives deep insight into designing efficient electrolytes in Li-metal batteries.

Correction for ‘Crystalline boron monosulfide nanosheets with tunable bandgaps’ by Haruki Kusaka et al., J. Mater. Chem. A, 2021, 9, 24631–24640, DOI: 10.1039/D1TA03307G.