High-performance LiMnPO4/C nanoplates synthesized by negative pressure immersion and a solid state reaction using nanoporous Mn2O3 precursors

Abstract

Preparing high-performance LiMnPO₄ is still a large obstacle due to its sluggish electrochemical kinetics. To overcome this problem, a novel method is developed for LiMnPO₄/C nanoplates from nanoporous Mn₂O₃ precursors. There are two advantages. Firstly, through negative pressure immersion, lithium dihydrogen phosphate (LiH₂PO₄), lithium hydroxide (LiOH) and sucrose (C₁₂H₂₂O₁₁) are deposited on the surface of porous Mn₂O₃ nanosheets. In the following solid-state reaction, three dimensional continuous conductive carbon is wrapped uniformly around the LiMnPO₄/C nanoplates, which greatly improved the conductivity. Secondly, (010) exposed facets are obtained using the Mn₂O₃ hierarchical microspheres as precursors, which allows for a fast transmission of Li⁺ ions improving the rate capability. As a result, the as-synthesized L-Mn₂O₃-LMP/C samples exhibit a superior rate performance with discharge capacities of 157.3 mA h g⁻¹ at C/20, 122.6 mA h g⁻¹ at 1C, and 105.8 mA h g⁻¹ at 2C. Meanwhile, they can retain 99.3% of the initial capacity after 100 cycles at 1C, revealing an excellent cycling stability. This method sheds more light on the fabrication of high-performance LiMnPO₄/C cathode materials and is suitable for large scale productions.