Driven by the increasing plea for greener transportation and efficient integration of renewable energy sources, Ni-rich metal layered oxides, namely NMC, Li [Ni1−x−yCoyMnz] O2 (x + y ≤ 0.4), and NCA, Li [Ni1−x−yCoxAly] O2, cathode materials have garnered huge attention for the development of Next-Generation lithium-ion batteries (LIBs). The impetus behind such huge celebrity includes their higher capacity and cost effectiveness when compared to the-state-of-the-art LiCoO2 (LCO) and other low Ni content NMC versions. However, despite all the beneficial attributes, the large-scale deployment of Ni-rich NMC based LIBs poses a technical challenge due to less stability of the cathode/electrolyte interphase (CEI) and diverse degradation processes that are associated with electrolyte decomposition, transition metal cation dissolution, cation–mixing, oxygen release reaction etc. Here, the potential degradation routes, recent efforts and enabling strategies for mitigating the core challenges of Ni-rich NMC cathode materials are presented and assessed. In the end, the review shed light on the perspectives for the future research directions of Ni-rich cathode materials.

No abstract

Building a lithium-ion cell with a third reference electrode which is stable and does not disturb the cell characteristics promises deep insights into the cell performance and aging behavior. In this study, a lithium titanium oxide coated aluminum mesh is introduced into lab size 28 mAh pouch cells, which allows the cells to be braced as usual. The influence of inserting the coated mesh together with an additional separator is analyzed using electrochemical impedance spectroscopy and cyclic aging tests. Cells with this reference electrode show small deviations in the Nyquist plot and an increased capacity fade compared to the standard cells. Nonetheless, these 3-electrode cells already allowed C-rate performance tests in a fresh and aged cell state. According to this, the charge current profiles for fresh and aged cells are optimized as step wise protocols to improve the utilization of the anode overpotential reserve while avoiding lithium plating. In order to realize this, the aged cells require a 60% slower protocol. This work shows that the overpotentials on the anode side increase during aging, which makes the cells more susceptible to lithium plating. However, compared to a constant current charge, a reduction in charging time of 30% is possible.

Possible alternative fuels such as ethanol and methanol can cause corrosion in mixture preparation systems, in contrast to the conventional petrol and diesel fuels. This phenomenon is due less to the pure alcohols than to the pollutions and additives. Electrochemical corrosion measurements were carried out on four selected steels, the influence of each constituent being investigated. The results of these measurements are given and it is shown that the corrosion problems can in most cases be controlled by means of the inhibitors morpholine, piperazine and hexamethylenediamine.Mogliche Alternativkraftstoffe wie Ethanol und Methanol konnen im Unterschied zu konventionellen Benzin-und Dieselkraftstoffen in Gemischaufbereitungssystemen Korrosion verursachen. Dieses Phanomen ist weniger auf die reinen Alkohole zuriickzufiihren als vielmehr auf Verunreinigungen und Zusatze. An vier ausgewahlten Stahlen wurden elektrochemische Korrosionsmessungen durchgefiihrt, wobei der EinfluB jedes einzelnen Kraftstoffbestandteils getrennt erfaljt wurde. Die Ergebnisse dieser Messungen werden mitgeteilt, und es wird gezeigt, daR die Korrosion in den meisten Fallen durch Zugabe der Inhibitoren Morpholin, Piperazin und Hexamethylendiamin auf vertretbare Werte herabgesetzt werden kann.

Lithium ion batteries are the enabler for electric vehicles and, hereby, a sustainable and green mobility in the future. However, there are high requirements regarding electric vehicles which can be translated into great demands of life time and sustainibility on cell level. Ni-rich Li[Ni x Mn y Co z ]O 2 (NMC), where x ≥ 0.6, became the state of the art electrode material for the positive electrode to meet energy and power demands. However, further optimization is required to increase the life time and safety of those materials. An approach is the change from polycrystalline NMC to single crystals to increase the intrinsic stability by suppressing degradation phenomena like particle cracking. In this work, we show that particle cracking is still an issue for monocrystalline Ni-rich NMC811 under moderate abusive conditions. Intragranular cracking, i.e. cracking within the primary particle, was revealed as a result of structural degradation of the NMC structure accompanied with oxygen release and cross-talks which affected the SEI and, ultimately, accelerated the ageing of the single crystal NMC811 containing cell compared to its polycrystalline counterpart.