Search

Abstract: The lithium ion batteries using Li4Ti5O12 as the anode material are easily being inflated during charge and discharge, which, however, does not occur in the batteries using graphite as the anode material. The high reduction reactivity of electrolyte on the Li4Ti5O12 material may be the main reason. In this work, the reduction reactivities of electrolyte on the uncoated and carbon-coated Li4Ti5O12 electrodes are compared for the first time. The results show that the reduction decomposition of electrolyte does occur on the uncoated Li4Ti5O12 electrode at around 0.7V, while it only takes place at the first cycle on the carbon-coated Li4Ti5O12 electrode. The carbon coating layers cover the catalytic active sites of Li4Ti5O12 particles and separate the Li4Ti5O12 particles from the electrolyte. A successive solid electrolyte interface (SEI) film is formed on the carbon layer during the formation process, which can prevent the further reduction decomposition of electrolyte at around 0.7V. The impurity phases of rutile and anatase TiO2 do not influence the reduction reactivity of electrolyte. This work is not only important to understand the reduction decomposition mechanism of electrolyte on the Li4Ti5O12 electrode, but also provides an effective solution to suppress the reduction decomposition of electrolyte in the batteries. [Copyright &y& Elsevier]

Abstract Efficient lithium-ion electrodes with impressive long-life cycling and high-rate performance are badly in need for large-scale energy storage systems, but it is challenging as well because of large volume expansion during lithium storage. Here through a facile and general strategy, we construct yolk-shell ZnCo 2 O 4 (Y-ZCO) spheres as an efficient anode for LIBs. The method involves a simple solvothermal process and subsequent annealing in air. The as-prepared Y-ZCO spheres reveal a high structural robustness and porous textural property. When acted as electrode material for LIBs, these Y-ZCO spheres show enhanced electrochemical performances. It displays a high specific capacity (1138 mA h g−1 at a current rate of 0.2 A g−1), superior capacity retention, and long-cycling stability (103.5% capacity retention ratio at 0.2 A g−1 for 100 cycles and 92.3% capacity retention ratio at 1 A g−1 for 300 cycles). All these results reveal that the Y-ZCO spheres could be potential anode materials for rechargeable batteries. More importantly, the present route is expedient and facile. It can be expected that the strategy could be spread to prepare other hollow mixed metal oxides with complex interior structures. Highlights • Yolk-shell ZnCo 2 O 4 spheres (Y-ZCO) are prepared by carbon-templating solvothermal synthesis. • The Y-ZCO anode shows excellent rate performance and cycling stability. • The Y-ZCO anode shows high structural robustness. [ABSTRACT FROM AUTHOR]