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Graphene oxide assisted template-free synthesis of nanoscale splode-like NiCo2O4 hollow microsphere with superior lithium storage properties

Rong, Haibo, Jiang, Zhongqing, Tian, Xiaoning, Qin, Yanmin, Cheng, Si, Wang, Fu, Jiang, Zhong-Jie
Journal of colloid and interface science 2018 v.511 pp. 119-127
Ostwald ripening, anodes, electrochemistry, graphene oxide, lithium, lithium batteries, microparticles
A facile template-free Ostwald ripening method is developed for the preparation of the reduced graphene oxide supported splode-like NiCo2O4 hollow microsphere (SNHM/rGO). The graphene oxide used in the reaction mixture is found to play a crucial role in the formation of the SNHM/rGO. It promotes the formation of the NiCo-glycerol microspheres suitable for the Ostwald ripening to form the reduced graphene oxide supported hollow NiCo-glycerol microspheres, which is important for the subsequent calcination to form the SNHM/rGO. The obtained SNHM/rGO shows a great promise as the anode for lithium-ion batteries and can deliver a stable reversible capacity of 1048.1 mA h g⁻¹ at the current density of 100 mA g⁻¹. The performance of the SNHM/rGO is much higher than that of most NiCo2O4-based materials reported previously, strongly suggesting that the SNHM/rGO could be used as the anode for practical applications. This is well supported by the higher performance of the LiCoO2//SNHM−rGO full cell. The excellent electrochemical performance can be attributed to the specific structure of the SNHM/rGO, which comprises the splode-like hollow NiCo2O4 microspheres with the reduced graphene oxide integrated.