Fabrication of porous MnO microspheres with carbon coating for lithium ion battery application

Abstract

Porous manganese oxide (Mn₂O₃) microspheres with a narrow size distribution have been successfully synthesized by the decomposition of a MnCO₃ precursor, which was obtained by a facile process with the assistance of glycine, Na₂SO₄ and poly(sodium-p-styrenesulfonate) (PSS). Experimental evidence reveals that the additive agents are beneficial to control the size and agglomeration of microspheres. The growth mechanism has been proposed on the basis of control experiments. The porous MnO microspheres with carbon coating (MnO@C) were generated after a carbonization process using pyrrole as a carbon source. Electrochemical results showed that the as-prepared MnO@C achieves a reversible capacity of 625 mAh g⁻¹ after 60 cycles at a current density of 100 mA g⁻¹ and capacities of 560, 422 and 308 mAh g⁻¹ at current densities of 200, 400 and 800 mA g⁻¹, respectively. Compared with porous Mn₂O₃, the enhanced cycling and rate performances are mainly attributed to the carbon coating, which could efficiently buffer the volume change during the lithiation/delithiation and improve the electronic conductivity among MnO particles.