Synthesis of Sn doped and rice husk derived activated carbon surface coating NMC 811 through solution combustion method.

Nickel rich cathode material is widely used in lithium-ion batteries due to its high capacity, low cost, and environmentally friendly. However, high nickel content leads to capacity decay, poor rate capability, thermal and structural instability. To overcome these drawbacks, in this work, nickel rich NMC 811 was doped with tin to form LiNi0.8Mn0.1Co0.1-xSnxO2 with x = 0.01, 0.03, 0.05 via solution combustion method. Crystal structure, morphology, particle size, surface area and electrochemical performance were characterized and analyzed. The optimum Sn-doped NMC 811 was further surface modified with rice husk derived activated carbon. Electrochemical characterization showed that dual modification with 3% Sn-doping and rice husk derived activated carbon coating (NMC-Sn/C) provided the highest conductivity of 1.73 × 10-4 S/cm, which was higher than that of NMC without modification (1.88 × 10-5 S/cm). The capacity reached 84.60 mAh/g with retention of 75% after 50 cycles. These improvements originate from the stabilizing effect of Sn-doping and rice husk derived activated carbon coating that reduces the direct contact between NMC 811 and electrolyte. Hence, modifications with Sn-doping and rice husk derived activated carbon coating are promising to enhance the electrochemical performance of NMC 811.

Explanation of the Colour Change in Alexandrites.

Alexandrites are remarkable and rare gemstones. They display an extraordinary colour change according to the ambient lighting, from emerald green in daylight to ruby red in incandescent light from tungsten lamps or candles. While this colour change has been correctly attributed to chromium impurities and their absorption band in the yellow region of the visible light spectrum, no adequate explanation of the mechanism has been given. Here, the alexandrite effect is fully explained by considering the von Kries model of the human colour constancy mechanism. This implies that our colour constancy mechanism is real (objective) and primarily attuned to correct for the colour temperature of black-body illuminants.

A single-device universal logic gate based on a magnetically enhanced memristor.

Memristors are one of the most promising candidates for future information and communications technology (ICT) architectures. Two experimental proofs of concept are presented based on the intermixing of spintronic and memristive effects into a single device, a magnetically enhanced memristor (MEM). By exploiting the interaction between the memristance and the giant magnetoresistance (GMR), a universal implication (IMP) logic gate based on a single MEM device is realized.