Green Template-Free Synthesis of Hierarchical Shuttle-Shaped Mesoporous ZnFe2O4 Microrods with Enhanced Lithium Storage for Advanced Li-Ion Batteries

In the work, a facile and green two-step synthetic strategy was purposefully developed to efficiently fabricate hierarchical shuttle-shaped mesoporous ZnFe2O4 microrods (MRs) with a high tap density of approximate to 0.85gcm(3), which were assembled by 1D nanofiber (NF) subunits, and further utilized as a long-life anode for advanced Li-ion batteries. The significant role of the mixed solvent of glycerin and water in the formation of such hierarchical mesoporous MRs was systematically investigated. After 488 cycles at a large current rate of 1000mAg(-1), the resulting ZnFe2O4 MRs with high loading of approximate to 1.4mg per electrode still preserved a reversible capacity as large as approximate to 542mAhg(-1). Furthermore, an initial charge capacity of approximate to 1150mAhg(-1) is delivered by the ZnFe2O4 anode at 100mAg(-1), resulting in a high Coulombic efficiency of approximate to 76% for the first cycle. The superior Li-storage properties of the as-obtained ZnFe2O4 were rationally associated with its mesoprous micro-/nanostructures and 1D nanoscaled building blocks, which accelerated the electron transportation, facilitated Li+ transfer rate, buffered the large volume variations during repeated discharge/charge processes, and provided rich electrode-electrolyte sur-/interfaces for efficient lithium storage, particularly at high rates.