Poly L-lysine (PLL)-mediated Porous Hematite Clusters as Anode Materials for Improved Li-Ion Batteries

Abstract

Porous hematite clusters were prepared as anode materials for improved Li-ion batteries. First, poly-L-lysine (PLL)-linked Fe3O4 was facilely prepared via cross-linking between the positive amine groups of PLL and carboxylate-bound Fe3O4. The subsequent calcination transformed the PLL-linked Fe3O4 into porous hematite clusters (Fe2O3@PLL) consisting of spherical alpha-Fe3O4 particles. Compared with standard Fe2O3, Fe3O4@PLL exhibited improved electrochemical performance as anode materials. The discharge capacity of Fe2O3@PLL was retained at 814.7 mAh g(-1) after 30 cycles, which is equivalent to 80.4% of the second discharge capacity, whereas standard Fe2O3 exhibited a retention capacity of 352.3 mAh g(-1). The improved electrochemical performance of Fe2O3@PLL was mainly attributed to the porous hematite clusters with mesoporosity (20 - 40 nm), which was beneficial for facilitating ion transport, suggesting a useful guideline for the design of porous architectures with higher retention capacity.