TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The method (P1) involves heating first mixture (F1) to first temperature (T1) at rate of 1-5 degrees C/minute, and then sintering at 300-700 degrees C, to obtain the first sintering product which is cooled at 10-60 degrees C, and mixing with carbon additive to obtain the second mixture (F2); and heating (F2) to the second temperature (T2) at rate of 2-100 degrees C/minute, and sintering at 650-900 degrees C for 5-20 hours. The method (P1) further involves grinding and briquetting (F2) before sintering to provide (F2) with compact density of 2.5-4 gram/cm3. The lithium, iron and phosphorus compounds of (F1) provide Li:Fe:P molar ratios of 0.9-1.2:0.95-1:1. The sintering processes are carried out in inert or reducing atmosphere. Preferred Components: The first mixture (F1) contains carbon additive 0.5-20 (preferably 5-15) wt.%; and the weight ratio of the carbon additive contained in (F2) to the carbon additive contained in (F1) is 1-10:1 (preferably 1-5:1); and further contains metal M-containing compound selected from oxides, hydroxides and carbonates of Mg, Mn, Ca, Sn, Co, Ni, Cr, Zr and Mo; and the lithium compound, metal M-containing compound, iron compound and phosphorus compound of (F1) provide Li:M:Fe:P molar ratios of 0.9-1.2:0.01-0.05:0.95-1:1. The lithium compound is selected from Li2CO3, LiOH, Li2C2O4, CH3COOLi, LiH2PO4 and Li3PO4; the iron compound is selected from Fe2C2O4, Fe(CH3COO)2, FeCl2, FeSO4 and Fe3(PO4)2, Fe2O3, FePO4, Fe(NO3)3 and Fe3O4; the phosphorus compound is selected from NH4H2PO4, (NH4)2HPO4, Li3PO4 and (NH4)3PO4. The carbon additive is selected from soluble starch, polyvinyl alcohol, polyethylene glycol, sucrose, glucose, urea, artificial graphite, natural graphite, superconducting acetylene black, acetylene black, fumed silicon, and various types of carbon black. The carbon additive contained in (F1) is selected from sucrose, glucose and urea.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The carbon additive is selected from benzene naphthalene phenanthrene copolymer, benzene phenanthrene binary copolymer, benzene anthracene binary copolymer, polypropylene, polyacrylamide, phenolic resin, furfural resin, urea-formaldehyde resin, and epoxy resin. EXAMPLE - Lithium Carbonate (0.1 mole), ferrous oxalate 2-hydrate (0.2 mole), ammonium phosphate (0.2 mole), glucose (1.4 g) and ethanol (250 ml) were mixed to provide Li:Fe:P molar ratio of 1:1:1, and the mixture (1) was ground for 12 hours at 300 revolutions per minute (rpm), and then dried at 70 degrees C. In an argon flow rate of 10 L/min, the mixture of (1) was heated to 450 degrees C at rate of 2 degrees C/min, maintained at this temperature for 6 hours, and then cooled to room temperature. Sucrose and ethanol (100 ml) were added, and then the mixture (2) was ground for 1 hour at 150 rpm, and dried at 70 degrees C. The mixture (2) was heated to 700 degrees C at rate of 10 degrees C/min, maintained at this temperature for 10 hours, and after work up to provide carbon-doped lithium iron phosphate (LiFePO4) composite powder. LiFePO4 composite material (100 g) was combined with polyvinylidene fluoride (PVDF) binder (5 g), acetylene black (5 g), and N-methylpyrrolidone (NMP) (50 g). The slurry was applied 20 microns thick to each side of aluminum foil, to provide LiFePO4 (cathode) (2.8 g). Natural graphite (100 g) was combined with conductive acetylene black (5 g), PVDF binder (5 g), and NMP (100 g). The slurry was applied 12 microns thick to each side of copper foil, to provide natural graphite (anode) (2.6 g). Each of the cathode and anode was separately wound with polypropylene film into lithium secondary battery core, after work up to provide separate lithium secondary batteries. The discharge performance showed (%) was 98, 96, 91 at 1C, 2C, 5C discharge currents respectively.