Synthesis And Electrochemical Performance Of A Nano-LiTi₂（PO₄）₃ Anode For Aqueous Lithium-ion Batteries

Aqueous lithium-ion batterieshave a lot of advantages,such as low price, clean and green, safety performance.In theory, it has broad application prospects and the potential to become a new energy storage device.Anode material is one of the key materials of aqueous lithium-ion batteries.In recent years,NASICON structure of Li Ti2(PO4)3 has aroused more concern.Material which is used to synthesis Li Ti2(PO4)3 is a large abundance, environmentally friendly, and it has a suitable electrode potential and good electrochemical reversibility, It is an appropriate anode material candidate ofaqueous lithium-ion batteries.But low intrinsic conductivity of Li Ti2(PO4)3 seriously affects the electrochemical properties of materials,and limits its practical application.In this paper, we expect to improve the electrochemical performance of Li Ti2(PO4)3.Adopt high-temperature solid-phase method and sol-gel method to prepare Li Ti2(PO4)3 and composite of Li Ti2(PO4)3/C. Li Ti2(PO4)3/C composites by high-temperature solid-phase method is milled different time. Water is removed by evaporation with different ways, and the carbon was coated different content.The crystal structure of synthetic products, surface morphology are characterized and analyzed by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Electrochemical properties of the materials is tested and analyzed by cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS) and constant current charge-discharge test. Study the influence of the particle size, the milling time, in addition to water ways, and the amount on the electrochemical properties of carbon-coated Li Ti2(PO4)3.Influence of milling time on the solid-phase synthesis Li Ti2(PO4)3/C:synthesize Li Ti2(PO4)3withlithiumcarbonate,titanium tetraisopropoxide,citricacid, diammonium hydrogen phosphate, hydrogen peroxide, ammonia.Coating carbon to obtain Li Ti2(PO4)3/C, and optimize the best milling time. The results showed that,Li Ti2(PO4)3/C which milled 10 hours has better charge-discharge capacity, and higher capacity retention rate efficiency. The first charge and discharge capacity of Li Ti2(PO4)3/C of milling 10 hours at 4C rate were 130 m Ah/g and 123 m Ah/g, and the efficiency is 94.65%; after charge-discharge 12 cycles the capacity is 109 m Ah/g and 98 m Ah/g, and the efficiency is 89.9%.Different ways dispersing carbon to remove water and the amount of carbon-coated have effects on the electrochemical performance of Li Ti2(PO4)3/C. When carbon in a rotary evaporator to obtain a decentralized manner and carbon coated is about 3.6%, it has best electrode electrochemical properties. After charge-discharge 200 cycles, the capacity remains 85%, the efficiency about remains 95%.