Improved electrochemical performances of LiMnPO4 synthesized by a hydrothermal method for Li-ion supercapatteries

• Published in: Journal of materials science. Materials in electronics 2018-11, Vol.29 (21), p.18553-18565
• Main Authors: Priyadharsini, Natarjan, Shanmugavani, Amirthalingam, Surendran, Subramani, Senthilkumar, Baskar, Vasylechko, Leonid, Kalai Selvan, Ramakrishnan
• Format: Article
• Language: English
• Subjects: Activated carbon; Aqueous electrolytes; Capacitance; Characterization and Evaluation of Materials; Charge transfer; Chemical synthesis; Chemistry and Materials Science; Crystal structure; Flux density; Hydrothermal crystal growth; Lithium compounds; Materials Science; Morphology; Optical and Electronic Materials; Performance enhancement; Phosphates; Sol-gel processes
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-018-9972-5

Developing high-performance positrode materials are essential to attain high energy supercapatteries. In this regard, the electrochemical performances of the hydrothermally synthesized LiMnPO 4 are studied. The crystal structures of the materials are elucidated using Full-profile XRD Rietveld refinement. The LiMnPO 4 particles showed uniform elongated spherical shape with rice-like morphology. The rice-like LiMnPO 4 showed a higher specific capacity of 492 C g −1 at 2 mV s −1 than highly agglomerated particles synthesized through sol–gel thermolysis method (191 C g −1 ) in 1 M LiOH aqueous electrolyte. The supercapattery is fabricated with rice-like LiMnPO 4 and activated carbon (AC) as positrode and negatrode, respectively. The supercapattery (AC||LMP-H) delivered a higher capacitance around 99 F g −1 along with an improved energy density of 31 Wh kg −1 . On the other hand, the LiMnPO 4 prepared by sol–gel thermolysis method exhibited a very low capacitance of 35 F g −1 at 0.6 mA for the fabricated device (AC||LMP-S) with the lesser energy density about 11 Wh Kg −1 at a power density of 198 W kg −1 . The reason behind the improved performance is explained based on the crystal structure as well as lower charge transfer resistance.