This perspective discusses the prospective strategies for overcoming the stability and capacity trade-off associated with increased Ni content in layered Ni-rich Li[NixCo¬yMnz]O2 (NCM) and Li[NixCoyAlz]O2 (NCA) cathodes. The Ni-rich NCM and NCA cathodes have largely replaced the LiCoO2 cathodes in commercial batteries because of their lower cost, higher energy density, good rate capability, and reliability that has been extensively field-tested. Nevertheless, they suffer from microcrack generation along grain boundaries and Ni3+/4+ reactivity that rapidly deteriorate electrochemical performance. Doping and coating have been efficient strategies in delaying the onset of the damage, but they fail to overcome the degradation. There are, however, alternative novel strategies that directly counter the inherent degradation through micro- and nano-structural modifications of the Ni-rich NCM and NCA cathodes.

Electrochemical water splitting is one of the most promising approaches for sustainable energy conversion and storage toward a future hydrogen society. This demands durable and affordable electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). In this study, we report the preparation of uniform Ni–P–O, Ni–S–O, and Ni–S–P–O electrocatalytic films on nickel foam (NF) substrates via flow cell-assisted electrodeposition. Remarkably, electrodeposition onto 12 cm² substrates was optimized by strategically varying critical parameters. The high quality and reproducibility of the materials is attributed to the use of a 3D-printed flow cell with a tailored design. Then, the as-fabricated electrodes were tested for overall water splitting in the same flow cell under alkaline conditions. The best-performing sample, NiSP/NF, required relatively low overpotentials of 93 mV for the HER and 259 mV for the OER to produce a current density of 10 mA cm⁻². Importantly, the electrodeposited films underwent oxidation into amorphous nickel (oxy)hydroxides and oxidized S and P species, improving both HER and OER performance. The superior electrocatalytic performance of the Ni–S–P–O films originates from the unique reconstruction process during the HER/OER. Furthermore, the overall water splitting test using the NiSP/NF couple required a low cell voltage of only 1.85 V to deliver a current density of 100 mA cm⁻². Overall, we demonstrate that high-quality electrocatalysts can be obtained using a simple and reproducible electrodeposition method in a robust 3D-printed flow cell.