The synthesis of energy materials

In this issue, we focus on the preparation of various materials used for applications in energy science and technology.

Materials for energy applications, such as anodes, cathodes and electrolytes for batteries, are of great importance for powering the world we live in. In this issue of Nature Synthesis, we present a range of articles which showcase advancements in the synthesis of energy materials.

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Featured on the cover of this issue, an Article by Zhang, Wang, Liu, Wu, Luo and co-workers reports a recrystallization approach to directly convert commercial polycrystalline lithium into a range of monocrystalline lithium metal anodes with single facets. Despite being a promising anode material for high-energy-density batteries, the application of lithium metal anodes is often limited by the formation of dendrites at practical current densities. Prepared by this recrystallization approach, monocrystalline lithium metal anodes, in particular, Li(110), show good mechanical properties, and solid-state batteries with Li(110) anodes display high-critical-current-density and cycling stability. A News & Views by Liu, Qin and Lu describes how controlling the nucleation and growth of metals through the reported recrystallization and crystal plane engineering strategy may also be applied in the preparation of other metal anodes, such as sodium, potassium and zinc. Using this approach could prohibit dendrite growth and enhance the lifetime and safety performance of metal anodes.

Protonic ceramic electrolysis cells (PCECs) produce fuels, such as H₂ and ethylene, through electrolysis. The common architecture of PCECs is a sandwich structure with a central dense electrolyte membrane. BaZr_0.8Y_0.2O_3−δ is a promising electrolyte material for PCECs, however, its usage is hindered due to the high sintering temperatures required for protonic devices. An Article by Dong, Luo, Li, Ding and co-workers reports a co-sintering process, in which the shrinkage stress of a readily sinterable support layer helps to densify the pure BaZr_0.8Y_0.2O_3−δ electrolyte membrane at low temperatures. Protonic zirconate cells prepared in this way demonstrate excellent Faradaic efficiency and electrochemical stability, enabling stabilized protonic cells for future energy applications.

Additionally, several research highlights in this issue discuss promising recent advances in the synthesis of energy materials. A Research Highlight based on work by Wakamiya and co-workers describes the design of alkoxy-substituted quaternary ammonium cations, without any β-protons, for use in ionic liquids. The ionic liquids prepared using this approach can be applied as electrolytes in fluoride-ion batteries, because they do not suffer from Hofmann elimination as many commercial ionic liquids composed of β-proton-containing quaternary ammonium cations do.

A Research Highlight based on an article by Wang and co-workers discusses the preparation of a hard-carbon-derived interphase on an aluminium current collector to construct anode-less sodium batteries with enhanced stability of sodium plating and stripping. This approach prevents the formation of sodium dendrites and minimizes sodium consumption, paving the way for the development of high-energy-density, low-cost sodium batteries.

Furthermore, a Research Highlight based on the work of Wang, Xu and co-workers reports a recrystallized hydrogen-bonded organic framework electrolyte with short-distance Zn²⁺ hopping sites, allowing high ionic conductivity at room temperature in solid-state zinc-ion batteries. Interestingly, adding AgNO₃ during the preparation of the framework is found to optimize the position of the conduction sites by forming Ag–N coordination bonds.

Finally, a Research Highlight based on an article by Wang, Yang, Li, Nan and co-workers describes the synthesis of nanocomposites of ferroelectric and dielectric materials featuring dendritic nanopolar regions for use in dielectric capacitors. While dielectrics are promising for energy storage applications, they can suffer from low energy density and efficiency. In this work, PbZr_0.53Ti_0.47O₃–MgO nanocomposites are prepared, combining the wide band gap of MgO with the ferroelectric properties of PbZr_0.53Ti_0.47O₃, leading to dielectric capacitors with high energy density and stability.

The research presented in this Focus issue provides some excellent examples of the types of articles we aim to publish in Nature Synthesis on the synthesis of materials for energy applications. The most important factor that we consider when assessing articles for publication is the level of synthetic advance presented within the manuscript. This can include the synthesis of the material itself (be it a new material or an improvement in the preparation of a known material), or how a particular synthesis approach leads to improvement in the performance of a material for its application, or an advance in our mechanistic understanding of the material synthesis. In all cases, thorough characterization data are required, along with sufficient experimental and theoretical evidence to support any claims made. Importantly, comparison of performance metrics to relevant literature should be included to provide context for the metrics.

We are witnessing a period of great progress in the synthesis of energy materials, and we look forward to seeing what advancements come next.