| Lithium-ion batteries(LIBs)have achieved great successes in the past decades for consumer electronics,electric vehicles(EV)and smart grids.However,the limited resources of lithium on earth are insufficient to satify the growing demand of these applications.Moreover,organic electrolytes in LIBs cause the serious safety concerns.To address the above two problems,two types of rechargeable batteries have been developed,sodium-ion batteries(SIBs)and solid-state batteries(SSBs).SIBs are developed due to the high element abundance of Na on earth,which well fits for massive energy storage applications.SSBs are designed to address the issues related to organic electrolytes,which also improves the energy density.In this thesis,we report the simple processes to synthesiz anode material P4Se3 and solid electrolyte Li1.3Al0.3Ti1.7(PO4)3(LATP)powders,and examined their electrochemical performances.The main results are listed as follows:1)P4Se3 particles are successfully synthesized by the simple heating of selenium and phosphorus at a low temperature.The orthorhombic-phase particles exhibit a high reversible capacity of 654 mA h g-1 at 200 mA g-1 after 70 cycles and a good rate capability about 486 mA h g-1 at 3 A g-1 in SIBs.The underlying electrochemical reactions are uncovered by ex-situ XRD patterns.The kinetic analysis from the CV curves at different scan rates,confirms the considerable contribution from the capacitive behaviors.2)Al-doped LTP powders,Li1.3Al0.3Ti1.7(PO4)3,are synthesized by a sol-gel process asissted by poly(vinyl alcohol)(PVA).Compared with the conventional solid state reaction,the sol-gel process promote the uniform doping of Al,thereby improving the ionic conductivity.At room temperature,its ionic conductivity is 1.5*10-4 S cm-1 and the activation energy for Li diffusion is 0.34 eV,both of which are better than the data observed in the powders prepared by the solid state reaction.The results indicate the potential of LATP as the solid electrolyte. |
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