Applications and Advantages of Atomic Layer Deposition for Lithium-Ion Batteries Cathodes: Review

Nowadays, lithium-ion batteries (LIBs) are one of the most convenient, reliable, and promising power sources for portable electronics, power tools, hybrid and electric vehicles. The characteristics of the positive electrode (cathode active material, CAM) significantly contribute to the battery’s functional properties. Applying various functional coatings is one of the productive ways to improve the work characteristics of lithium-ion batteries. Nowadays, there are many methods for depositing thin films on a material’s surface; among them, one of the most promising is atomic layer deposition (ALD). ALD allows for the formation of thin and uniform coatings on surfaces with complex geometric forms, including porous structures. This review is devoted to applying the ALD method in obtaining thin functional coatings for cathode materials and includes an overview of more than 100 publications. The most thoroughly investigated surface modifications are lithium cobalt oxide (LCO), lithium manganese spinel (LMO), lithium nickel-cobalt-manganese oxides (NCM), lithium-nickel-manganese spinel (LNMO), and lithium-manganese rich (LMR) cathode materials. The most studied processes of deposition are aluminum oxide (Al2O3), titanium dioxide (TiO2) and zirconium dioxide (ZrO2) films. The primary purposes of such studies are to find the synthesis parameters of films, to find the optimal coating thickness (e.g., ~1–2 nm for Al2O3, ~1 nm for ZrO2, 2, etc.), and to reveal the effect of the coating on the electrochemical parameters of batteries. The review summarizes synthesis conditions, investigation results of deposited films on CAMs and positive electrodes and some functional effects observed due to films obtained by ALD on cathodes

Atomic Layer Deposition of Li–Me–O Thin Films as Electrode Materials for Nanodevices Power Sources

The development of nanoscale power sources with a long battery life is now required for novel nanoelectronic devices, such as wireless sensors, biomedical implants, and smart cards. Lithiated metal oxides (Li–Me–O) are widely used in lithium-ion batteries (LIBs). Depending on the type of metal, Li–Me–O can be applied as cathode, anode, or electrolyte materials. Atomic layer deposition (ALD), due to its precision control over thickness, purity, and uniformity over large areas of applied coatings, can be applied for the synthesis of a different thin film LIBs materials. In the present work, the deposition of Li–Sn–O (anode) and Li–Al–O (electrolyte) by ALD is considered. The prepared films were investigated with the use of X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry

Influence of the Composition and Testing Modes on the Electrochemical Performance of Li-Rich Cathode Materials

Li-rich oxides are promising cathode materials for Li-ion batteries. In this work, a number of different compositions of Li-rich materials and various electrochemical testing modes were investigated. The structure, chemical composition, and morphology of the materials synthesized were studied by XRD with Rietveld refinement, ICP-OES, and SEM. The particle size distributions were determined by a laser analyzer. The galvanostatic intermittent titration technique and galvanostatic cycling with different potential limits at various current densities were used to study the materials. The electrochemical study showed that gradual increase in the upper voltage limit (formation cycles) was needed to improve further cycling of the cathode materials under study. A comparison of the data obtained in different voltage ranges showed that a lower cut-off potential of 2.5 V (2.5–4.7 V range) was required for a good cyclability with a high discharge capacity. An increase in the low cut-off potential to 3.0 V (3.0–4.8 V voltage range) did not improve the electrochemical performance of the oxides and, on the contrary, considerably decreased the discharge capacity and increased the capacity fade. The LMR35 cathode material (Li1.149Ni0.184Mn0.482Co0.184O2) demonstrated the best functional properties among all the compositions studied

Effects of Mg Doping at Different Positions in Li-Rich Mn-Based Cathode Material on Electrochemical Performance

Li-rich Mn-based layered oxides are among the most promising cathode materials for next-generation lithium-ion batteries, yet they suffer from capacity fading and voltage decay during cycling. The electrochemical performance of the material can be improved by doping with Mg. However, the effect of Mg doping at different positions (lithium or transition metals) remains unclear. Li1.2Mn0.54Ni0.13Co0.13O2 (LR) was synthesized by coprecipitation followed by a solid-state reaction. The coprecipitation stage was used to introduce Mg in TM layers (sample LR-Mg), and the solid-state reaction (st) was used to dope Mg in Li layers (LR-Mg(st)). The presence of magnesium at different positions was confirmed by XRD, XPS, and electrochemical studies. The investigations have shown that the introduction of Mg in TM layers is preferable in terms of the electrochemical performance. The sample doped with Mg at the TM positions shows better cyclability and higher discharge capacity than the undoped sample. The poor electrochemical properties of the sample doped with Mg at Li positions are due to the kinetic hindrance of oxidation of the manganese-containing species formed after activation of the Li2MnO3 component of the composite oxide. The oxide LR-Mg(st) demonstrates the lowest lithium-ion diffusion coefficient and the greatest polarization resistance compared to LR and LR-Mg

On the early history of atomic layer deposition: most significant works and applications

Atomic layer deposition (ALD) is a technique that has been instrumental in enabling the semiconductor industry to maintain its adherence to Moore’s Law, and is becoming a gamechanger in several other fields. A worldwide voluntary effort called “Virtual Project on the History of ALD” (VPHA), open for everyone with an ALD background to participate, was launched in summer 2013 to explore how the ALD concept was developed; which were the first ALD experiments; when, where, why and by whom they were made. Earlier VPHA outcomes were published at ALD 2014 (accessed through VPHA’s website http://vphald.com); VPHA has made steady progress since then. Here we will present a conclusive recommended reading list of the most significant early ALD publications and briefly review the most important individual works and applications. Acknowledgements: We are grateful for Dr. Tuomo Suntola’s general support during the VPHA and for Dr. Aziz Abdulagatov’s and Annina Titoff’s assistance in initiating it. The VPHA would not have been possible without the recent advances in professional social networking and cloud computing. RLP acknowledges partial funding from the Finnish Centre of Excellence in Atomic Layer Deposition. The author list is intentionally in alphabetical order