Engineering topics
Abakumov, Artem M.
Publications and source records attributed to Abakumov, Artem M..
Structural evolution at the oxidative and reductive limits in the first electrochemical cycle of Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2
High-energy-density lithium-rich materials are of significant interest for advanced lithium-ion batteries, provided that several roadblocks, such as voltage fade and poor energy efficiency are removed. However, this remains challenging as their functioning mechanisms during first cycle are not fully understood. Here we enlarge the cycling potential window for Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 electrode, identifying novel structural evolution mechanism involving a structurally-densified single-phase A’ formed under harsh oxidizing conditions throughout the crystallites and not only at the surface, in contrast to previous beliefs. We also recover a majority of first-cycle capacity loss by applying a constant-voltage step on discharge. Using highly reducing conditions we obtain additional capacity via a new low-potential P” phase, which is involved into triggering oxygen redox on charge. Altogether, these results provide deeper insights into the structural-composition evolution of Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 and will help to find measures to cure voltage fade and improve energy efficiency in this class of material.
Expanding the Rich Crystal Chemistry of Ruthenium(V) Oxides via the Discovery of BaRu[subscript 2]O[subscript 6], Ba[subscript 5]Ru[subscript 4]O[subscript 15], Ba[subscript 2]Ru[subscript 3]O[subscript 10], and Sr[subscript 2]Ru[subscript 3]O[subscript 9](OH) by pH-Controlled Hydrothermal Synthesis
Abstract not provided
Reaching the Energy Density Limit of Layered O3‐NaNi 0.5 Mn 0.5 O 2 Electrodes via Dual Cu and Ti Substitution
Abstract Although being less competitive energy density‐wise, Na‐ion batteries are serious alternatives to Li‐ion ones for applications where cost and sustainability dominate. O3‐type sodium layered oxides could partially overcome the energy limitation, but their practical use is plagued by a reaction process that enlists numerous phase changes and volume variations while additionally being moisture sensitive. Here, it is shown that the double substitution of Ti for Mn and Cu for Ni in O3‐NaNi 0.5− y Cu y Mn 0.5− z Ti z O 2 can alleviate most of these issues. Among this series, electrodes with specific compositions are identified that can reversibly release and uptake ≈0.9 sodium per formula unit via a smooth voltage‐composition profile enlisting minor lattice volume changes upon cycling as opposed to Δ V / V ≈23% in the parent NaNi 0.5 Mn 0.5 O 2 while showing a greater resistance against moisture. The positive attributes of substitution are rationalized by structure considerations supported by density functional theory (DFT) calculations. Electrodes with sustained capacities of ≈180 mAh g −1 are successfully implemented into 18 650 Na‐ion cells having greater performances, energy density‐wise (≈250 Wh L −1 ), than today's Na 3 V 2 (PO 4 ) 2 F 3 /HC Na‐ion technology which excels in rate capabilities. These results constitute a step forward in increasing the practicality of Na‐ion technology with additional opportunities for applications in which energy density prevails over rate capability.