Institute of Fundamental Technological Research

In this current work, the pristine LiNi0.5Mn1.5O4 (LNMO) and fluorine-doped LiNi0.5Mn1.5O4–xFx (x = 0.1; 0.2; 0.3) cathode materials were successfully synthesized through a facile spray-drying method. The performed morphological and structural characterizations revealed that the fluorine doping led to a partial conversion of Mn4+ to Mn3+ ions in LNMO structure and an increase of their average particle sizes. These characteristics made the LiNi0.5Mn1.5O3.9F0.1 cathode exhibited the best rate capability at high C-rates and cycling performance among all investigated LNMO-based electrodes. Its improved electrochemical properties resulted from excellent crystallinity, high Li+ diffusion coefficient, and low charge-transfer resistance. Moreover, the LiNi0.5Mn1.5O3.9F0.1 electrode was found to possess the excellent resistant against Mn dissolution at elevated temperature. According to its great thermal stability, an impressive capacity retention of 81.5% after 100-cycle at 0.2 C at elevated temperature was achieved. In terms of the facile synthesis approach, superior electrochemical performances, and great thermal stability, the LiNi0.5Mn1.5O3.9F0.1 electrode synthesized by the scalable spray-drying method can be regarded as a promising high-voltage cathode material for high-performance Li-ion batteries.

Cathode material, Fluorine doping, Spinel LiNi0.5Mn1.5O4, Spray-drying synthesis, Li-ion batteries

Li4Ti5O12 (LTO) is a promising anode material for lithium-ion batteries (LIBs) due to its stable reversibility, high-rate cyclability, and high operational potential. On the other hand, it suffers from poor electronic conductivity and low capacitance. To overcome these disadvantages, modification of the LTO surface is frequently undertaken. Considering this idea, the production of a biomass-derived carbon-coated LTO material (LTO/C) and its application as an anode in LIBs is described in this work. The carbon precursor was obtained from commercial carrot juice, which was degraded using microwaves. According to the UV studies, the carbon precursor revealed similar properties to carbon quantum dots. Then, it was deposited on LTO synthetized through a sol-gel method. The LTO/C electrode exhibited a high specific capacity of 211 mAhg−1 at 0.1 C. Capacity retention equal to 53% of the initial value was found for the charge–discharge rate increase from 0.1 C to 20 C. The excellent electrochemical performance of LTO/C was caused by the carbon coating, which provided (i) short diffusion pathways for the Li+ ions into the LTO structure and (ii) enhanced electronic conductivity. The obtained results indicated that biomass-derived carbon quantum dot-coated LTO can be considered as a promising anode for LIBs.

anode material, biomass-derived carbon, carbon coating, carbon quantum dot, lithium-ion battery