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论文类型：期刊论文

发表时间：2015-07-14

发表刊物：JOURNAL OF MATERIALS CHEMISTRY A

收录刊物：SCIE、EI、Scopus

卷号：3

期号：26

页面范围：13920-13925

ISSN号：2050-7488

摘要：Lithium manganese phosphate, LiMnPO4 (LMP), has 20% higher redox potential than that of LiFePO4, and is thus considered a potential cathode replacement material for LiFePO4 in lithium ion batteries. However, its cyclic stability and rate performance are restricted by the sluggish kinetics of electron and lithium ion migration in it. A high-efficiency two-step microwave solvothermal method has been established to synthesize carbon-coated LMP nanoparticles and the reaction conditions have been investigated in detail. In particular, nanocrystals with more active planes for efficient Li+ extraction and insertion can be selectively synthesized. This is of great importance for the preparation of a high performance LMP electrode material for Li-ion batteries. The synthesis and carbon coating of LMP were both performed using microwave irradiation, which shortens the time required to only a couple of minutes. A sample synthesized at 160 degrees C for 10 min exhibits a high and constant reversible capacity of 155 mA h g(-1) at 0.5 C (theoretical capacity: 170 mA h g(-1)) even after 100 cycles and shows outstanding rate performance. For example, a high capacity of 118 mA h g(-1) was obtained at 10 C, which to our knowledge has never been previously reported. Moreover, the sample has an excellent low-temperature performance with 140 mA h g(-1) at 0.5 C at 8 degrees C and 133 mA h g(-1) at 2 degrees C. Such an excellent electrochemical performance can be attributed to the (020) plane of nanosized LMP, regular micromorphology and high conductivity of a uniform carbon coating containing some elemental nitrogen. The reported process is potentially scalable with a much shorter synthesis time than existing methods.