Development of High-Throughput Methods for Sodium-Ion Battery Cathodes

Abstract

Combinatorial synthesis of Li-ion batteries has proven extremely powerful in screening complex compositional spaces for next-generation materials. To date, no Na-ion counterpart exists wherein Na-ion cathodes can be synthesized in such a way to be comparable to that obtained in bulk synthesis. Herein, we develop a synthesis route wherein hundreds of milligram-scale powder samples can be made in a total time of 3 days. We focus on materials in the Na−Fe−Mn−O pseudoternary system of high immediate interest. Using a sol−gel method, developed herein, yields both phase-pure combinatorial samples of Na 2/3 Fe 1/2 Mn 1/2 O 2 and NaFe 1/2 Mn 1/2 O 2 , consistent with previous reports on bulk samples of interest commercially. By contrast, the synthesis route used for Li-ion cathodes (namely coprecipitations) does not yield phase pure materials, suggesting that the sol−gel method is more effective in mixing the Na, Fe, and Mn than coprecipitation. This has important consequences for all attempts to make these materials, even in bulk. Finally, we demonstrate that these milligram-scale powder samples can be tested electrochemically in a combinatorial cell. The resulting cyclic voltammograms are in excellent agreement with those found on bulk samples in the literature. This demonstrates that the methodology developed here will be effective in characterizing the hundreds of samples needed to understand the complex ternary systems of interest and that such results will scale-up well to the gram and kilogram scale.

Toward autonomous design and synthesis of novel inorganic materials

“…The promising developments for automated solution-based syntheses of organic molecules have led to several recent efforts that demonstrate the automation of inorganic materials syntheses using similar methods. To rapidly produce lithium and sodium metal oxides sampling varied compositions, for example, a batch solution-based approach was partially automated using the robotic system depicted in Figure 4 18,19 . This platform uses an electronic pipetting tool to transfer stock solutions of precursors into microplates, which are heated to mediate reactions between the starting materials.…”

“…product before firing at high temperature. Reproduced with permission 19 . Copyright 2020, American Chemical Society.…”

“…As discussed in Section 2.1, the full automation of solution-based syntheses can be achieved by using electronic and programmable syringe pumps to transfer samples between modules that perform unit operations such as mixing, heating, and filtration 11,13 . Although most existing applications deal with organic molecules, recent work has shown that similar techniques can be used to automate the synthesis of inorganic materials through sol-gel or precipitation methods [18][19][20] , which are useful to produce nanoparticles (e.g., metal oxides) so long as there exist appropriate precursors with high solubilities in common solvents such as water. To expand the scope of compounds that can be made by solution-based techniques, hydrothermal synthesis may also be applied in future automated platforms.…”

“…Within the thin film community, for example, HT automation of synthesis and characterization is routinely carried out to probe the effects of composition and processing conditions on the properties of resulting samples [14][15][16] . Similar methods have also been used to study bulk powders but are generally more limited with respect to the scope of compounds that can be dealt with [17][18][19] . Existing workflows are restricted to materials with readily available synthesis recipes, which precludes the discovery of completely novel systems with new and interesting properties.…”

Towards autonomous high-throughput multiscale modelling of battery interfaces

“…[155][156][157][158][159] A high-throughput and combinatorial experimentation approach is effective and reliable to prepare a huge number of interface materials over a broader compositional region in an appreciably short period of time. [155][156][157][158] Methods such as post-synthesis array transfer, 158 thin-film combinatorial method, 160,161 combinatorial robot system, combinatorial magnetron sputtering and pulsed laser deposition, 155,162 multi-component additive screening, 163 and the sol-gel approach 164 allow rapid investigation of different SEI materials as a function of the synthesis parameters. While examples of high-throughput experiments for the synthesis of SEI materials have been discussed in the literature, they are still relatively limited, and more efforts should be devoted to enhancing their scalability.…”