Development of high energy density solid-state batteries with Li metal anodes has been limited by uncontrollable growth of Li dendrites in liquid and solid electrolytes (SEs). This, in part, may be caused by a dearth of information about mechanical properties of Li, especially at the nano- and microlength scales and microstructures relevant to Li batteries. We investigate Li electrodeposited in a commercial LiCoO2/LiPON/Cu solid-state thin-film cell, grown in situ in a scanning electron microscope equipped with nanomechanical capabilities. Experiments demonstrate that Li was preferentially deposited at the LiPON/Cu interface along the valleys that mimic the domain boundaries of underlying LiCoO2 (cathode). Cryogenic electron microscopy analysis of electrodeposited Li revealed a single-crystalline microstructure, and in situ nanocompression experiments on nano-pillars with 360–759 nm diameters revealed their average Young's modulus to be 6.76 ± 2.88 GPa with an average yield stress of 16.0 ± 6.82 MPa, ~24x higher than what has been reported for bulk polycrystalline Li. We discuss mechanical deformation mechanisms, stiffness, and strength of nano-sized electrodeposited Li in the framework of its microstructure and dislocation-governed nanoscale plasticity of crystals, and place it in the parameter space of existing knowledge on small-scale Li mechanics. The enhanced strength of Li at small scales may explain why it can penetrate and fracture through much stiffer and harder SEs than theoretically predicted.

With today's rapidly increasing demand for lithium-ion batteries (LIBs) for emerging applications, such as electric vehicles (EVs) and large-scale grid storage, it begs the question of how sustainable batteries really are. Proponents of increasing electrification of our modern society often tout the environmental benefits of using battery energy storage over traditional fossil fuels, citing direct reductions in greenhouse gas emissions, especially when paired with renewable energy generation. Unfortunately, these often leave out considerations for the “dark side” of LIBs that few manufacturers in the battery industry have addressed: how to deal with batteries at their end of life. As the world accelerates toward displacing conventional vehicles with EVs, methods of handling large volumes of spent LIBs when these devices reach their end of life have not been fully developed. This potentially results in the accumulation of battery waste that will ultimately undo the environmental benefits batteries originally sought to achieve.

Ammonia can supplement hydrogen gas as a clean fuel to combat climate change. It overcomes hindrances that currently impede the realization of the full potential of hydrogen gas, including economical storage, political commitment, and safety concerns.