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In this study, carbon-coated porous nanofibers were prepared via electrospinning and the performance of Li[Ni 0.93 Co 0.07 ]O 2 (NC) synthesized by electrospinning (E-NC) and co-precipitation (C-NC) was compared. E-NC had a discharge capacity of 206 mAh g -1 at 0.1C (17 mA/g), which is 10% higher than that of C-NC (189.2 mAh g -1 ). E-NC shows a high-rate performance of 118.32 mAh g -1 (61.7%) at 5C (850 mA/g), which is 50% higher than that of C-NC (78.22 mAh g -1 = 45.7%). Charge transfer of the carbon-coated porous nanofiber E-NC decreased by 35% compared to C-NC after 20 cycles as observed using electrochemical impedance spectroscopy. The results of this study show that the nanofiber structure with carbon coating shortens the Li-ion diffusion path, improves electrical conductivity, resulting in excellent rate performance.

Nickel-rich layered Li(Ni-Ni0.9Co0.1)O2 is a promising cathode material due to its high specific capacity. However, commercial application of this material is impeded by its rapid capacity degradation associated with structural instability. In this work, 0.01mol Al3+ Doped Li(Ni-Ni0.9Co0.1)O2 cathode material is prepared by heat treatment of a mixture of stoichiometric amounts of nano-sized Al(OH)3 powders, co-precipitated (Ni-Ni0.9Co0.1)(OH)2 precursors, and LiOH·H2O. The results show that Al3+ doping significantly improves the cycling properties of Li(Ni-Ni0.9Co0.1)O2 cathode material. Under a voltage range of 3–4.5 V, 0.02 mol% Al3+ doped Li(Ni-Ni0.9Co0.1)O2 cathode material shows an initial discharge capacity of 210 mAh/g at 0.1C, with a capacity retention of 97% for subsequent 100 cycles at 1C at room temperature. In contrast, bare Li(Ni-Ni0.9Co0.1)O2 shows a capacity retention of only ~62.8% under the same conditions, with an initial specific discharge capacity of 220 mAh/g. The improvement in cycling performance is attributed to stabilization of the layered structure by Al3+ , mitigated migration of Ni2+ to the Li layer, improved lithium diffusion kinetics and reduced lattice expansion/shrinkage during cycling. Stabilization of the layered structure by Al3+ doping is further reflected by the observation of fewer cracks in cathode electrodes after prolonged cycling.

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