LITHIUM-ION BATTERIES HAVE BEEN CONSIDERED AS AN ATTRACTIVE POWER SOURCE FOR A WIDE VARIETY OF APPLICATION [1-4]. LIFEPO4/CARBON COMPOSITE cathode MATERIALS WERE SYNTHESIZED BY A SOL-GEL PROCESS. THE COMPOSITE SYNTHESIZED VIA CARBON BLACK, CITRIC ACID AND SUCROSE IN THE DEVELOPED SOL-GEL PROCESS. THE CARBON BLACK IN THIS RESEARCH SHOWS THE HIGHEST CONDUCTIVITY, HIGHEST SPECIFIC CAPACITY, AND BEST CAPABILITY AMONG THE SYNTHESIZED MATERIALS. THE PRODUCTS WERE ANALYZED BY X-RAY DIFFRACTION (XRD) AND FT-IR SPECTROSCOPY. THE PROPERTIES OF LIFEPO4/C AS ACTIVE CATHODIC MATERIAL WASSTUDIED IN STANDARD COIN CELL.THE RESULTS CONFIRMED LOW ELECTRICAL RESISTANCE FOR THE PREPARED ELECTROD.

IN AN ATTEMPT TO UNDERSTAND THE EFFECT OF SYNTHESIS CONCENTRATION UPON ELECTROCHEMICAL PERFORMANCE OF LICOO2, THE COMPOUND WAS SYNTHESIZED AT THREE DIFFERENT MOLAR RATIO OF LITHIUM: COBALT, VIZ., 1: 1, 1.3: 1 AND 1.7: 1 USING A NOVEL FLAME SPRAY PYROLYSIS METHOD. CHARGE-DISCHARGE CURVES AND CYCLIC VOLTAMMETRY STUDIES EVIDENCE THAT LICOO2 SYNTHESIZED AT RATIO OF 1.7: 1 EXHIBITS BETTER ELECTROCHEMICAL CYCLING BEHAVIOR. IT IS FOUND THAT LICOO2 NANOPARTICLES, SHOWS A HIGH CAPACITY OF 126 MAH G-1 AT 0.1 C IN THE FIRST CYCLE AND A REVERSIBLE CAPACITY OF 103 MAH G-1 AT 0.1 C IN THE 3TH CYCLE. BASED ON OUR EXPERIMENTAL OBSERVATIONS AND CONJECTURE ON THE PARTICLE FORMATION, THE PROPERTIES OF NANOPARTICLES SUCH AS PARTICLE SIZE AND CRYSTALLINE PHASE CAN BE CONTROLLED BY THE GAS FLOW RATES AND PRECURSOR CONCENTRATION. IN THE PRESENT STUDY, WE SYNTHESIZED THE CRYSTALLINE LICOO2 NANOPARTICLES, WHICH IS FAVORABLE FOR THE APPLICATION TO THE cathode MATERIAL.

THE INFLUENCE OF DOPING WAS INVESTIGATED ON THE PROPERTIES OF LAYERED LI1.2MN0.54NI0.13CO0.13O2 WITH A A-NAFEO2 PREPARED USING LICH3COO.2H2O, MN (CH3COO) 2.4H2O, NI (CH3COO) 2.4H2O AND CO (CH3COO) 2.4H2O VIA HYDROTHERMAL REACTION. X-RAY DIFFRACTION (XRD), TRANSMISSION ELECTRON MICROSCOPY (TEM), CHARGE-DISCHARGE AND ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY (EIS) TESTS WERE APPLIED TO INVESTIGATE STRUCTURE, MORPHOLOGY AND ELECTROCHEMICAL PERFORMANCE OF THE LITHIUM-RICH DOPED SAMPLE. XRD ANALYSIS CONFIRMS THAT THE UNIFORM SOLID SOLUTION HAS BEEN FORMED IN THE AS-PREPARED COMPOUND WITHOUT ANY IMPURITIES. IT IS SHOWN THAT THE CRYSTAL LATTICE PARAMETERS (A, C) OF THE DOPED COMPOUND IS BIGGER THAN PRISTINE COMPOUND. TEM IMAGE OF THE COMPOUND SHOWS THAT CUBIC-LIKE MICROPARTICLES WITH A MEAN GRAIN SIZE OF 600 NM HAVE BEEN FORMED. GALVANOSTATIC CHARGE-DISCHARGE TEST EXHIBITS THAT DOPED SAMPLE HAS A DISCHARGE CAPACITY OF 257 MAH.G-1 IN THE VOLTAGE RANGE OF 2-4.8V. EIS RESULTS DEMONSTRATE THAT DOPING DECREASES CHARGE TRANSFER RESISTANCE AND ENHANCES CONDUCTIVITY AND REACTION KINETICS DUE TO HIGH CURRENT IONS AND ELECTRONS OF THE DOPED ELEMENT.

RECHARGEABLE LI-S BATTERIES HAVE RECEIVED EVER-INCREASING ATTENTION RECENTLY DUE TO THEIR HIGH THEORETICAL SPECIFIC ENERGY DENSITY, WHICH IS 3 TO 5 TIMES HIGHER THAN THAT OF LI-ION BATTERIES BASED ON INTERCALATION REACTIONS. LI-S BATTERIES MAY REPRESENT A NEXT-GENERATION ENERGY STORAGE SYSTEM. HOWEVER, IT HAS BEEN REPORTED THAT LI-S BATTERIES WITH ORGANIC LIQUID ELECTROLYTE HAVE SOME PROBLEMS RELATED TO LOW ACTIVE MATERIALS UTILIZATION EFFICIENCY AND POOR CYCLE LIFE, BECAUSE OF THE INSULATING NATURE OF SULFUR AND THE SOLUBILITY OF POLYSULFIDES GENERATED DURING THE ELECTROCHEMICAL REACTION PROCESS [1]. IN THIS RESEARCH, TO SOLVE THESE PROBLEMS, MESOPOROUS CARBON (CMK-1) WAS SYNTHESIZED AND IT WAS USED TO ABSORB THE POLYSULFIDE WHICH FORMS DURING THE FIRST DISCHARGE STEP OF A LI/S battery. CMK-1 IN THE ELECTRODE NOT ONLY ACTS AS AN ADSORBENT FOR THE POLYSULFIDE, BUT ALSO ACTS AS AN ELECTRICALLY CONDUCTING ADDITIVE [2]. CMK1- S NANOCOMPOSITE WITH WEIGHT RATIOS OF 70:30, 60:40 AND 50:50 WERE PREPARED BY HEATING THE MIXTURE OF SULFUR AND CMK-1 AT 155O FOR 4H UNDER N2 PROTECTION [3]. DIFFERENT TECHNIQUE SUCH AS DSC/TGA, ICP, XRD, TEM AND BET WERE EMPLOYED TO CHARACTERIZE THE CHEMICAL COMPOSITION, SURFACE AREA, PORE AND VOLUME SIZE AND MORPHOLOGY OF ELECTRODE MATERIALS. FINALLY THE ELECTROCHEMICAL PERFORMANCE OF CMK1-S NANOCOMPOSITE WAS INVESTIGATED BY CHARGE-DISCHARGE AND CYCLIC VOLTAMMETRY METHODS. THE RESULTING OF THESE TESTS REPRESENTING A PROMISING cathode MATERIAL FOR RECHARGEABLE LITHIUM BATTERIES WITH HIGH ENERGY DENSITY.

OLIVINE STRUCTURED LIFEPO4 IS ONE OF THE PROMISING MATERIALS OF LITHIUM ION battery cathode, IN TERMS OF PRICE, SAFETY, RATE, AND CYCLE LIFE. IN THIS STUDY, LIFEPO4-C WAS SYNTHESIZED BY SPRAY PYROLYSIS TECHNIQUE TO APPLY AS LITHIUM ION battery cathode. SPRAY PYROLYSIS IS A SIMPLE, CONTINUOUS, AND EASILY CONTROLLABLE TECHNIQUE FOR SYNTHESIS OF NANOMATERIALS. V2O5 POWDER WAS ALSO ADDED TO cathode TO FURTHER PROMOTE THE ELECTROCHEMICAL PERFORMANCE TOWARDS LITHIUM ION STORAGE. THE ELECTROCHEMICAL PERFORMANCE WAS EVALUATED BY GALVANOSTATIC CHARGE-DISCHARGE, CYCLIC VOLTAMMETRY, AND ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY IN A TWO-ELECTRODE CELL. THE RESULTS SHOWED THE BENEFICIAL ROLE OF THE ADDITION OF V2O5 IN TERMS OF IMPROVING THE SPECIFIC CAPACITY, RATE CAPABILITY, AND CYCLING STABILITY AND LITHIUM ION DIFFUSION RATE OF THE LIFEPO4-C-BASED cathode. THE OBTAINED ELECTROCHEMICAL PERFORMANCE METRICS WAS AS FOLLOWS: THE INITIAL DISCHARGE CAPACITY OF 154 MAHG-1 AT 0.1C AND 110 MAHG -1 AT 100 MAHG-1 RATE, AND KEEPING A CAPACITY RETENTION RATIO OF 93% AFTER 50 CYCLES.