Yachun Liang

A Single-Step Hydrothermal Route to 3D Hierarchical Cu2O/CuO/rGO Nanosheets as High-Performance Anode of Lithium-Ion Batteries

As anodes of Li-ion batteries, copper oxides (CuO) have a high theoretical specific capacity (674 mA h g-1 ) but own poor cyclic stability owing to the large volume expansion and low conductivity in charges/discharges. Incorporating reduced graphene oxide (rGO) into CuO anodes with conventional methods fails to build robust interaction between rGO and CuO to efficiently improve the overall anode performance. Here, Cu2 O/CuO/reduced graphene oxides (Cu2 O/CuO/rGO) with a 3D hierarchical nanostructure are synthesized with a facile, single-step hydrothermal method. The Cu2 O/CuO/rGO anode exhibits remarkable cyclic and high-rate performances, and particularly the anode with 25 wt% rGO owns the best performance among all samples, delivering a record capacity of 550 mA h g-1 at 0.5 C after 100 cycles. The pronounced performances are attributed to the highly efficient charge transfer in CuO nanosheets encapsulated in rGO network and the mitigated volume expansion of the anode owing to its robust 3D hierarchical nanostructure.

Assembly of anisotropic one dimensional Ag nanostructures through orientated attachment: on-axis or off-axis growth?

Recently it has been found that one dimensional (1D) Ag nano-structures can be synthesized through oriented attachment (OA) growth. In OA growth of 1D structures, nanoparticles (NPs) attach to the growing nanorods (NRs) via either on-axis or off-axis attachment. However, the thermodynamic basis for understanding the preference of each growth mode has remained unexplored until now. In this paper, molecular static calculations are performed to investigate the van der Waals interactions (vdW) in both on-axis and off-axis attachments of 1D Ag nano-structures. The correlation of parameters including the size, aspect ratio (AR), crystalline orientation of NR, the inter-particle separation and the off-axis approaching angle, with both OA attachments is investigated in detail. The results show that off-axis attachment is thermodynamically favorable compared to on-axis attachment in a typical OA growth, and straight on-axis OA growth are typically realized by tuning the other aspects of an OA growth system. Interestingly, it is found that the off-axis growth is both precursor-size dependent and crystalline-orientation dependent.