X-ray photoelectron spectroscopy (XPS) is a key method for studying (electro-)chemical changes in metal-ion battery electrode materials. In a recent publication, we pointed out a conflict in binding energy (BE) scale referencing at alkali metal samples, which is manifested in systematic deviations of the BEs up to several eV due to a specific interaction between the highly reactive alkali metal in contact with non-conducting surrounding species. The consequences of this phenomenon for XPS data interpretation are discussed in the present manuscript. Investigations of phenomena at surface-electrolyte interphase regions for a wide range of materials for both lithium and sodium-based applications are explained, ranging from oxide-based cathode materials via alloys and carbon-based anodes including appropriate reference chemicals. Depending on material class and alkaline content, specific solutions are proposed for choosing the correct reference BE to accurately define the BE scale. In conclusion, the different approaches for the use of reference elements, such as aliphatic carbon, implanted noble gas or surface metals, partially lack practicability and can lead to misinterpretation for application in battery materials. Thus, this manuscript provides exemplary alternative solutions.

The thermal atomic layer deposition (ALD) of copper oxide films from the nonfluorinated yet liquid precursor bis(tri- <mml:math display="inline"><mml:mi>n</mml:mi></mml:math>n -butylphosphane)copper(I)acetylacetonate, <mml:math display="inline"><mml:mrow><mml:mo>[</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mmultiscripts><mml:mi mathvariant="normal">B</mml:mi><mml:mprescripts></mml:mprescripts><mml:none></mml:none><mml:mi>n</mml:mi></mml:mmultiscripts><mml:msub><mml:mi mathvariant="normal">u</mml:mi><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:mi mathvariant="normal">P</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mmultiscripts><mml:mi mathvariant="normal">C</mml:mi><mml:mprescripts></mml:mprescripts><mml:mrow><mml:mn>2</mml:mn></mml:mrow><mml:none></mml:none></mml:mmultiscripts><mml:mi mathvariant="normal">u</mml:mi><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mi>acac</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:mo>]</mml:mo></mml:mrow></mml:math>[(Bnu3P)C2u(acac)] , and wet <mml:math display="inline"><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math>O2 on Ta, TaN, Ru, and <mml:math display="inline"><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>SiO2 substrates at temperatures of <mml:math display="inline"><mml:mrow><mml:mo><</mml:mo><mml:mn>160</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math><160°C is reported. Typical temperature-independent growth was observed at least up to <mml:math display="inline"><mml:mrow><mml:mn>125</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>125°C with a growth-per-cycle of <mml:math display="inline"><mml:mrow><mml:mo>∼</mml:mo><mml:mn>0.1</mml:mn><mml:mspace width="0.3em"></mml:mspace><mml:mi mathvariant="normal">Å</mml:mi></mml:mrow></mml:math>∼0.1Å for the metallic substrates and an ALD window extending down to <mml:math display="inline"><mml:mrow><mml:mn>100</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>100°C for Ru. On <mml:math display="inline"><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>SiO2 and TaN, the ALD window was observed between 110 and <mml:math display="inline"><mml:mrow><mml:mn>125</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>125°C , with saturated growth shown on TaN still at <mml:math display="inline"><mml:mrow><mml:mn>135</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>135°C . Precursor self-decomposition in a chemical vapor deposition mode led to bimodal growth on Ta, resulting in the parallel formation of continuous films and isolated clusters. This effect was not observed on TaN up to <mml:math display="inline"><mml:mrow><mml:mo>∼</mml:mo><mml:mn>130</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>∼130°C and neither on Ru or <mml:math display="inline"><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>SiO2 for any processing temperature. The degree of nitridation of the tantalum nitride underlayers considerably influenced the film growth. With excellent adhesion of the ALD films on all substrates studied, the results are a promising basis for Cu seed layer ALD applicable to electrochemical Cu metallization in interconnects of ultralarge-scale integrated circuits.