lightweight, and compact and allow for versatile device geometries. They must also be scalable and offer high energy density to provide improved packing efficiency and longer device operation. Although both Ni-MH batteries and LIBs have been commercialized since the 1990s, [1] LIBs possess twice the gravimetric/volumetric energy density (250 Wh kg −1 /700 Wh L −1 vs 170 Wh kg −1 /350 Wh L −1 ), [2] higher battery voltage (3.7 V vs 1.2 V), and longer cycle life with lower self-discharge, [3] contributing tremendously to the proliferation of portable electronic devices (e.g., mobile phones, laptops, cameras, tablets) as well as emerging new technologies such as wearable electronic devices (e.g., smart watches and sport-related tracking devices). Their high gravimetric/ volumetric energy density, [2] excellent cycle life (thousands of cycles), and lack of the memory effect have positioned LIBs as state-of-the-art power sources and one of the greatest successes of modern electrochemistry, revolutionizing the way we acquire, process, transmit, and share information globally. Nevertheless, advances in battery energy density, safety, costs, and flexibility in shape and size are still needed to keep up with the rapidly growing demand for devices with even longer runtime as well as real-time data collection and transmission capabilities in addition to increasingly energy-demanding applications such as electric vehicles (EVs) and electricity grid storage. Even though LIBs were first commercialized in all electric vehicles (EVs) in 2010 and also emerged for grid application in the same time frame, the low energy density (≈250 Wh kg −1 ) and high average cost (≈$156 kWh −1 in 2019) of conventional LIBs do not meet the requirements for advanced EVs and grid-scale energy storage. [4][5][6] Specifically, the driving range per charge (miles), which is related to the energy density of each cell, and the cost are important parameters for EVs. For example, one 85 kWh battery pack in a Tesla Model S requires 7104 LIB cells, with an energy density of 265 Wh kg −1 , providing an average range of 250 miles, which is ahead of the range of other EVs but still behind the target of 375 miles. [4] In grid-scale applications, LIBs can be used for various tasks: frequency regulation, peak shaving, load leveling, and large-scale integration of renewable energies, with specific properties generally required for each task. For frequency regulation, LIBs need to provide a fast response, high rate performance, and high-power capability,The introduction of new, safe, and reliable solid-electrolyte chemistries and technologies can potentially overcome the challenges facing their liquid counterparts while widening the breadth of possible applications. Through tech-historic evolution and rationally analyzing the transition from liquidbased Li-ion batteries (LIBs) to all-solid-state Li-metal batteries (ASSLBs), a roadmap for the development of a successful oxide and sulfide-based ASSLB focusing on interfacial challenges is introduced, while accounting ...

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Nucleation of nanoparticles using the exsolution phenomenon is a promising pathway to design durable and active materials for catalysis and renewable energy. Here, we focus on the impact of surface orientation of the host lattice on the nucleation dynamics to resolve questions with regards to “preferential nucleation sites”. For this, we carried out a systematic model study on three differently oriented perovskite thin films. Remarkably, in contrast to the previous bulk powder-based study suggesting that the (110)-surface is a preferred plane for exsolution, we identify that other planes such as (001)- and (111)-facets also reveal vigorous exsolution. Moreover, particle size and surface coverage vary significantly depending on the surface orientation. Exsolution of (111)-oriented film produces the largest number of particles, the smallest particle size, the deepest embedment, and the smallest and most uniform interparticle distance among the oriented films. Based on classic nucleation theory, we elucidate that the differences in interfacial energies as a function of substrate orientation play a crucial role in controlling the distinct morphology and nucleation behavior of exsolved nanoparticles. Our finding suggests new design principles for tunable solid-state catalyst or nanoscale metal decoration.

Nanoparticles formed on oxide surfaces are of key importance in many fields such as catalysis and renewable energy. Here, we control B-site exsolution via lattice strain to achieve a high degree of exsolution of nanoparticles in perovskite thin films: more than 1100 particles μm −2 with a particle size as small as ~5 nm can be achieved via strain control. Compressive-strained films show a larger number of exsolved particles as compared with tensile-strained films. Moreover, the strain-enhanced in situ growth of nanoparticles offers high thermal stability and coking resistance, a low reduction temperature (550 °C), rapid release of particles, and wide tunability. The mechanism of lattice strain-enhanced exsolution is illuminated by thermodynamic and kinetic aspects, emphasizing the unique role of the misfit-strain relaxation energy. This study provides critical insights not only into the design of new forms of nanostructures but also to applications ranging from catalysis, energy conversion/storage, nano-composites, nano-magnetism, to nano-optics.