Guochun Yan

Accurate construction of a hierarchical nickel–cobalt oxide multishell yolk–shell structure with large and ultrafast lithium storage capability

Novel hierarchical nickel–cobalt oxide microspheres with a multishell yolk–shell structure have been accurately synthesized via a facile and scalable method. The multishell yolk–shell powder shows a significantly improved electrochemical performance in terms of high reversible capacity, good rate capability and excellent cycling performance.

Synthesis of Cu2O/reduced graphene oxide composites as anode materials for lithium ion batteries

Abstract A facile way was used to synthesize Cu 2 O/reduced graphene oxide (rGO) composites with octahedron-like morphology in aqueous solution without any surfactant. TEM images of the obtained Cu 2 O/rGOs reveal that the Cu 2 O particles and rGO distribute hierarchically and the primary Cu 2 O particles are encapsulated well in the graphene nanosheets. The electrochemical performance of Cu 2 O/rGOs is enhanced compared with bare Cu 2 O when they are employed as anode materials for lithium ion batteries. The Cu 2 O/rGO composites maintain a reversible capacity of 348.4 mA·h/g after 50 cycles at a current density of 100 mA/g. In addition, the composites retain 305.8 mA·h/g after 60 cycles at various current densities of 50, 100, 200, 400 and 800 mA/g.

Lithium difluoro(oxalato)borate as an additive to suppress the aluminum corrosion in lithium bis(fluorosulfony)imide-based nonaqueous carbonate electrolyte

Lithium bis(fluorosulfony)imide (LiFSI) is a promising alternative lithium salt to replace lithium hexafluorophosphate (LiPF6) due to its high conductivity and excellent compatibility with electrode material. On the other hand, the aluminum corrosion caused by LiFSI hinders its application in lithium ion battery. To solve this problem, lithium difluoro(oxalato)borate (LiDFOB) is added to suppress the aluminum corrosion in LiFSI-based nonaqueous carbonate electrolyte. The electrochemical tests in three-electrode cells and graphite/LiCoO2 full cells confirm that the addition of LiDFOB is beneficial to suppress the aluminum corrosion. In addition, the mechanism is proposed that the oxidation products of LiDFOB form a passivating film at the aluminum surface to suppress the corrosion based on the experimental results from SEM and XPS tests.