High-rate layered lithium-rich cathode nanomaterials for lithium-ion batteries synthesized with the assist of carbon spheres templates

摘要

Nanoparticles of the layered lithium-rich cathode, Li[Li0.2Ni0.2Mn0.6]O-2, have been synthesized via the two-step hydrothermal reactions combined with calcination process, while carbon spheres were used as templates. In the first hydrothermal step, the carbon spheres templates are obtained, and then the Li [Li0.2Ni0.2Mn0.6]O-2 materials are prepared during the second hydrothermal step with addition of 0, 5, 10, 15 wt% as-prepared carbon spheres. Structural and morphological characterizations indicate the well ordered layer-structured lithium-rich nanomaterials can be obtained with adding proper amount of carbon spheres templates. The electrochemical test demonstrates that the sample added 10 wt% carbon spheres (LNMO-Cs10) exhibits the best performance among all the samples. It delivers the optimal cycling ability, the least voltage decay, and the maximal discharge capacities of 238.7, 219.3, 204.8 and 182.7 mAh g(-1) at 1C, 2C, 5C and 10C rates, respectively. EIS test shows that the LNMO-Cs10 material also has the reduced solid-electrolyte-interface resistance and charge transfer resistance. The excellent cycling ability and rate capability are possibly attributed to the better dispersibility of the nanoparticles with adding adequate amount of carbon spheres templates during materials synthesis. It can both guarantee the good contact between electrode and electrolytes and prevent high aggregation of nanoparticles. (C) 2016 Elsevier B.V. All rights reserved.