Green Template-Free Synthesis of Hierarchical Shuttle-Shaped Mesoporous ZnFe2 O4 Microrods with Enhanced Lithium Storage for Advanced Li-Ion Batteries.

Abstract

In the work, a facile and green two-step synthetic strategy was purposefully developed to efficiently fabricate hierarchical shuttle-shaped mesoporous ZnFe2 O4 microrods (MRs) with a high tap density of ∼0.85 g cm(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 1000 mA g(-1) , the resulting ZnFe2 O4 MRs with high loading of ∼1.4 mg per electrode still preserved a reversible capacity as large as ∼542 mAh g(-1) . Furthermore, an initial charge capacity of ∼1150 mAh g(-1) is delivered by the ZnFe2 O4 anode at 100 mA g(-1) , resulting in a high Coulombic efficiency of ∼76 % for the first cycle. The superior Li-storage properties of the as-obtained ZnFe2 O4 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.