“Layered”/“cation-ordered”/O3-type Li-TM-oxides (TM: transition metal) suffer from structural instability due to “TM migration” from the TM layer to the Li layer upon Li removal (viz., “cation disordering”). This phenomenon gets exacerbated upon excessive Li removal, with Ni ions being particularly prone to migration. When used as cathode material in Li-ion batteries, the “TM migration” and associated structural changes cause rapid impedance buildup and capacity fade, thus limiting the cell voltages to ≤4.3 V for stable operation and lowering the usable Li-storage capacity (concomitantly, energy density). Looking closely at the “TM migration” pathway, one realizes that the tetrahedral site (t-site) of the Li layer forms an intermediate site. Accordingly, the present work explores a new idea concerning suppression of “Ni migration” by “blocking” the intermediate crystallographic site (viz., the t-site) with a dopant, which is the most stable at that site. In this regard, density functional theory (DFT)-based simulations indicate that the concerned t-site is energetically the most preferred and stable site for d 10 Zn2+. Detailed analysis of crystallographic data (including bond valence sum) obtained with the as-prepared Zn-doped Li-NMC supports the same. Furthermore, the simulations also predict that Zn doping is likely to suppress “Ni migration” upon Li removal. Supporting these predictions, galvanostatic delithiation/lithiation studies with Zn-doped and undoped Li-NMCs demonstrate significantly improved cyclic stability, near-complete suppression of “cation mixing”, and negligible buildup of impedance (as well as potential hysteresis) for the former, even upon being subjected to long-term cycling using a high upper cut-off potential of 4.7 V (vs Li/Li+). Accordingly, such subtle tuning of the composition and structure, in the light of electronic configuration of the dopant and specific crystallographic site occupancy, is likely to pave the way toward the development of Ni-containing stable high voltage O3-type Li-TM-oxide cathodes for the next-generation Li-ion batteries.

Anode materials that exhibit high energy density, high power density, long life cycle, and better safety profile for lithium‐ion batteries are necessary for the development of electric vehicles. Computational and experimental studies to describe the relevant aspects of carbon allotropes as anode materials are discussed, toward the significant improvement of specific power and energy capacity. The role of types of carbon ring and mixed hybridization (sp, sp2, and sp3) in carbon‐based anode materials for Li storage explored. An overview is provided on the procedures used to analyze the storage properties of anode materials using first‐principles theoretical methods such as intercalation energy, volume expansion, and open circuit voltage. Finally, the progress, importance, design, and the challenges of carbon‐based anode materials are comprehensively discussed.

First-principles based calculations are performed to investigate the dehydrogenation kinetics considering doping at various layers of MgH2 (110) surface. Doping at first and second layer of MgH2 (110) has a significant role in lowering the H2 desorption (from surface) barrier energy, whereas the doping at third layer has no impact on the barrier energy. Molecular dynamics calculations are also performed to check the bonding strength, clusterization, and system stability. We study in details about the influence of doping on dehydrogenation, considering the screening factors such as formation enthalpy, bulk modulus, and gravimetric density. Screening based approach assist in finding Al and Sc as the best possible dopant in lowering of desorption temperature, while preserving similar gravimetric density and Bulk modulus as of pure MgH2 system. The electron localization function plot and population analysis illustrate that the bond between Dopant-Hydrogen is mainly covalent, which weaken the Mg-Hydrogen bonds. Overall we observed that Al as dopant is suitable and surface doping can help in lowering the desorption temperature. So layer dependent doping studies can help to find the best possible reversible hydride based hydrogen storage materials.

A higher Ni content with less cobalt usage of lithium nickel cobalt manganese oxide cathode materials (LiNi x Co0.1Mn0.1O2, 0.6 ⟨ x ⟩ 0.9) provides a higher power rating and higher energy density in lithium-ion batteries (LIBs). However, severe Li/Ni mixing is one of the main reasons for poor cycling stability in these materials. Cation doping effectively suppresses the mixing of Ni ions in the lithium layer of LiNi x Co0.1Mn0.1O2. In this work, we investigate the effects of different cationic dopants (D) such as zirconium (Zr4+), zinc (Zn2+), calcium (Ca2+), magnesium (Mg2+), and aluminum (Al3+) in the Li layer, which act as a pillar for preventing degradation in the LiNi0.8–y Co0.1Mn0.1D y O2 (y = 0.033) cathode material for LIBs using density functional theory. In particular, a substituted dopant at the Ni3+-ion site suppresses the Ni3+-ion migration to the Li layer. During Li de-intercalation, the dopant migrates to the Li layer and acts as a pillar that enhances the structural stability. The pillared systems of both pristine and doped structures exhibit a more improved performance than non-pillared systems. An Al3+-doped pillared system displays a reduction in the height of the Li slab layer, resulting in a high Li diffusion energy barrier, which hinders easy Li diffusivity. However, the pillared systems doped with Zr4+- and Ca2+- in LiNi0.8–y Co0.1Mn0.1D y O2 act as better pillar-ions due to their high suppression energy of “neighbor Ni3+-ion migration”, facile Li-ion diffusion, and enhanced electrochemical structural stability.