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Since the oil crisis occurs, the lithium-ion batteries as a new energy become a research hotspot. LiFePO 4 has a high specific capacity, good cycle performance, high-temperature charge and discharge performance, good thermal stability, environmental protection, low cost, etc., is expected to become the next generation of lithium-ion battery cathode material. However, conventional methods of LiFePO 4 tap density of the powder material is present a small drawback, the use by the glass crystallization of ways to get crystals containing lithium iron phosphate electrode materials can overcome this shortcoming. Stage of lithium iron phosphate glass of less and less systematic. Firstly, by melt - water quench cooling annealing or prepared by the method Li2 O -Fe 2 O 3 -P 2 < / sub> O 5 Series samples analyzed by XRD and polarized light microscopy to determine the Li2 O -Fe 2 O 3 -P 2 O 5 ternary system were investigated glass-forming region, prepare for the future and research Li2 O -Fe 2 O 3 -P 2 O 5 glass system provides a reference. Experiments using the Archimedes method and weight loss were measured density of the glass and chemical stability, through FTIR, DTA, XRD and other means to analyze the structure of glass, transition temperature (Tg) and crystallization behavior. When you have determined the glass-forming range, to maintain a constant component content, changing the content of the other two components studied composition changes on three yuan lithium iron phosphate glass structure and properties. The results showed that: Li 2 O and Fe 2 O 3 can raise three yuan lithium iron phosphate glass density; Fe 2 < / sub> O 3 can improve the chemical stability of the glass, the glass crystallization inhibition, while Li 2 O the opposite effect. In three yuan on the basis of lithium iron phosphate glass were introduced Na 2 O, K 2 O, CaO, MgO, BaO, ZnO replace Li 2 O, the introduction of SiO2 and B 2 O 3 replace P 2 O5 and Al 2 O 3 replace Fe 2 O 3 to prepare a series of lithium iron phosphate glass. Containing Na 2 O, K 2 O, CaO, MgO, BaO, ZnO quaternary lithium iron phosphate glass studies show: Na 2 O, K 2 O, MgO, CaO and BaO replace Li 2 O small amount, because Li 2 O content decreased, Li accumulation in the glass structure weakened, Tg decreased; while Na 2 O, K 2 O, MgO, CaO and BaO than Li 2 O large molar mass, the density of the glass increases, and because the mixed alkali effect and suppress the effects of substitution improves the chemical stability of the glass. With increasing substitution, as an additive has a large ionic radius, the smaller the migration ability to improve the glass transition temperature, but breakage of the glass structure increases the density of the glass decreases, lower chemical stability; ZnO substituted Li 2 O, the glass density, increased chemical stability, while the glass transition temperature decreased, ZnO amount introduced is small, ZnO in the glass structure, the role of the connecting network form [ZnO 4 ] tetrahedra and PO-Zn group, with the increase in ZnO, Zn2 gap in the glass structure. Experiments confirmed, SiO2 replace P 2 O 5 to improve the chemical stability of the glass, increasing the density of the glass, Tg and crystallization temperature (Tc); but its replacement can not exceed 10%, otherwise to obtain the glass. When Al 2 O 3 replace Fe 2 O 3 content of 10%, the Tg of the glass increases, density, chemical stability is improved, with Al 2 O 3 increases, the lower the Tg of the glass, the density decreases, lower chemical stability; small B < sub> 2 O 3 replace P 2 O 5 , its structure is formed in the glass [BO 4 < / sub>] tetrahedra resulting rapid increase in glass density, chemical stability is improved, but with the B 2 O 3 introduction increases, the glass portion of the structure [ BO 4 ] tetrahedral transition to [BO 3 ] triangular body, slowly increase the density of the glass, the chemical stability is lowered. Measured at different heating rates adding different amounts of quaternary oxides of lithium iron phosphate glass DTA curve. The DTA curve of glass, calculated activation energy of crystallization of glass and determines the heat treatment of the glass. Experimental results show that: with the Na 2 O, K 2 O introduced increases, the glass after heat treatment precipitation of crystals of the main phase from LiFeP 2 O7 gradually transformed into NaFeP 2 O 7 , KFeP 2 O 7 ; while the introduction of CaO, MgO, BaO, ZnO and SiO2 glass main phase precipitated crystals are LiFeP 2 O7; adding Al 2 O 3 lithium iron phosphate glass After heat treatment, in addition to precipitation of crystals LiFeP 2 O 7 outside the gradual emergence of Fe 7 (PO 4 ) 6 ; introducing B 2 O 3 glass after heat treatment precipitation LiFePO 4 crystals, and with the B 2 O 3 introduced increases, the precipitation of LiFePO 4 crystal volume increased.
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