Manganese Base Compound Preparation, Structure Characterization And Electrochemical Performance Of The Research

Nowadays, extensive use of electronic devices fuels the requirement ofhigh-performance batteries. To meet the need for high-performance lithium ionbatteries, it is essential to increase the efficiency and battery life of electrode materials.MnO2has been widely used in lithium ion batteries due to its high theoretical capacity,high discharge platform, stable structure, and low cost. In most previous reports,however, MnO2suffered from inefficient charge-discharge cycle performance, volumeexpansion, and other shortcomings. Herein, we report three kinds of stable MnO2composites with better battery performance.1. We prepare MnO2/C composites by directly reducing potassium permanganatevia different kinds of carbon materials. MnO2composites of different crystal formscan be prepared by using different dimensions of carbon materials. MnO2nanoflowerand nanowire are also prepared under optimized conditions. Different shape of MnO2composites are prepared by using different amount of carbon nanotubes.2. Nitrides as a kind of potential reservoir lithium anode materials, because of itspreparation conditions demanding, limits its application in commercial and scientificresearch. We achieve template-directed preparation of Mn3N2/C composites in anitrogen atmosphere and analyze their lithium storage properties via constant currentcharge and discharge. A reversible capacity of768mAh/g is achieved at constantcurrent of100mA/g. First coulomb efficiency is70.22%and the capacity is498mAh/g after20cycles at a discharge ratio of100mA/g. Compared to the templateprepared Mn3N2, the capacity retention increased by22%, combining with electronmicroscope and XRD data, the carbon template prepared Mn3N2grain size small anduniform, high reversible capacity and capacity retention rate is high, is expected tobecome the new development of high performance lithium ion battery cathodematerials.3. Micron-sized MnCO3lumps are firstly prepared, followed by calcining, etching andhydrothermal preparation of hollow core-shell structure of MnO2@TiO2by usinglumps as templates. The pore size and thickness of lumps can be regulated by changing conditions of heat treatment and pickling. The strengths of our preparedmaterials include unique hollow structure, the box body wall in open channel andsamples with high crystallinity. TiO2can inhibit volume expansion of MnO2in theprocess of charging and discharging lithium ion batteries, increase conductivity ofbatteries, and reduce the disproportionation of MnO2.