Atom-bond-connectivity index of certain graphs

The ABC index is one of the most applicable topological graph indices and several properties of it has been studied already due to its extensive chemical applications. Several variants of it have also been defined and used for several reasons. In this paper, we calculate the atom-bond connectivity index of some derived graphs such as double graphs, subdivision graphs and complements of some standard graphs.Publisher's Versio

Exploring the nanoscale origin of performance enhancement in Li1.1_{1.1}Ni0.35_{0.35}Mn0.55_{0.55}O2_2 batteries due to chemical doping

Despite significant potential as energy storage materials for electric vehicles due to their combination of high energy density per unit cost and reduced environmental and ethical concerns, Co-free lithium ion batteries based off layered Mn oxides presently lack the longevity and stability of their Co-containing counterparts. Here, we demonstrate a reduction in this performance gap via chemical doping, with Li$_{1.1}$Ni$_{0.35}$Mn$_{0.55}$O$_2$ achieving an initial discharge capacity of 159 mAhg$^{-1}$ at C/3 rate and a corresponding capacity retention of 94.3% after 150 cycles. We subsequently explore the nanoscale origins of this improvement through a combination of advanced diffraction, spectroscopy, and electron microscopy techniques, finding that optimized doping profiles lead to an improved structural and chemical compatibility between the two constituent sub-phases that characterize the layered Mn oxide system, resulting in the formation of unobstructed lithium ion pathways between them. We also directly observe a structural stabilization effect of the host compound near the surface using aberration corrected scanning transmission electron microscopy and integrated differential phase contrast imaging.Comment: 20 pages, 8 figure

Randic type SDI index of certain graphs

In this paper, we calculate the Randic type SDI index of double graphs, subdivision graphs and complements of some standard graphs.Publisher's Versio

Mitigating the Surface Degradation and Voltage Decay of Li_1.2Ni_0.13Mn_0.54Co_0.13O₂ Cathode Material through Surface Modification Using Li₂ZrO₃

In the quest to tackle the issue of surface degradation and voltage decay associated with Li-rich phases, Li-ion conductive Li₂ZrO₃ (LZO) is coated on Li_1.2Ni_0.13Mn_0.54Co_0.13O₂ (LNMC) by a simple wet chemical process. The LZO phase coated on LNMC, with a thickness of about 10 nm, provides a structural integrity and facilitates the ion pathways throughout the charge–discharge process, which results in significant improvement of the electrochemical performances. The surface-modified cathode material exhibits a reversible capacity of 225 mA h g^–1 (at C/5 rate) and retains 85% of the initial capacity after 100 cycles. Whereas, the uncoated pristine sample shows a capacity of 234 mA h g^–1 and retains only 57% of the initial capacity under identical conditions. Electrochemical impedance spectroscopy reveals that the LZO coating plays a vital role in stabilizing the interface between the electrode and electrolyte during cycling; thus, it alleviates material degradation and voltage fading and ameliorates the electrochemical performance