A series of polypyrrole (PPy)-LiNi

RAPET (Reactions under Autogenic Pressure at Elevated Temperature) method has been used to synthesize lithium titanium phosphate anode material. The prepared compound is characterized by X-ray diffraction analysis. The electrochemical behavior has been studied in different aqueous electrolytes using cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) techniques. CV peak current is proportional to the square root of scan rate. The system satisfies the required conditions for a reversible redox system. LiTi 2 (PO 4 ) 3 is found to undergo lithium insertion at all concentrations of LiNO 3 electrolyte. The values of -Z when all the points of the impedance spectra measured in 2 M Li 2 SO 4 electrolyte compared at 5 mHz are found to show a minimum at the potential close to the CV peak potential during charge and discharge. The cell, LiTi 2 (PO 4 ) 3 /2 M Li 2 SO 4 /LiNi 1/3 Mn 1/3 Co 1/3 O 2 delivers a discharge capacity of 116 mAh g −1 in the first cycle at an applied current of 0.2 mA cm −2 (C/5 rate ) and it retains a capacity of 107 mAh g −1 over 100 cycles with good rate capability. The non-aqueous cell, Li/1 M LiAsF 6 /EC-DMC/LiTi 2 (PO 4 ) 3 delivers a discharge capacity of 125 mAh g −1 with a voltage plateau around 2.4 V vs Li/Li + .

LiNi 1/3 Mn 1/3 Co 1/3 O 2 cathode material is synthesized by reactions under autogenic pressure at elevated temperature (RAPET) method and its electrochemical behavior is studied in 5 M LiNO 3 aqueous solution and compared with that in a nonaqueous electrolyte. In cyclic voltammetry, LiNi 1/3 Mn 1/3 Co 1/3 O 2 electrode exhibits a pair of reversible redox peaks and the corresponding potential plateaus were observed during charge-discharge cycle. Potentiostatic intermittent titration technique (PITT) and electrochemical impedance spectral (EIS) data measured at various potentials are analyzed to determine the kinetic parameters which characterize intercalation/deintercalation of lithium ions in both aqueous and nonaqueous electrolytes. A typical cell employing LiNi 1/3 Mn 1/3 Co 1/3 O 2 as cathode and LiTi 2 (PO 4 ) 3 as anode in 5 M LiNO 3 solution delivers an average output voltage of 1.0 V with a specific capacity of 84 mAh g −1 .