Alkali Metal Ion Selective Electrodes Based On Reversible Intercalate/deintercalate Materials

Carbon paste electrodes have some advantages such as: ease of preparation, low cost, renewal of surface, stability of response and so on. Wherein the selection of the active material is vital to the response performance of ion selective electrode（ISE）. In this thesis, a series of reversible deintercalation marterials were synthesized and used as active material of the ISE. The materials’ phase composition and morphology have been charactered by XRD and SEM. Dfferent electrochemical methods have been used to test the response performance, stability, reproducibility and detection limit of electrodes. The effects of different ratio of raw materials, modifier and ion doping on the response performance of electrode have also been studied.1) Li Mn₂O₄（LMO） was prepared by hydrothermal-synthesis-Mn O₂, which used as active material of lithium ISE（LMO-CPE）. Results showed that the electrode with optimum composition（50wt% of acetylene black, 30wt% of liquid paraffin and 20wt% of Li Mn₂O₄） had good response to Li+ and exhibited a good linear response of a good linear response of 60.7 m V/dec. and the detection limit was 5.16×10-6 mol/L. But due to the influence of Jahn-Teller effect, the potential drift phenomenon has been observed.2) PEDOT was served as modifier to modified the LMO-CPE. The electrode which was prepared with PEDOT（2wt% of Li Mn₂O₄） and LMO carbon paste through admixture method exhibited a Nernst response towards Li+, with a sensitivity of 59±2 m V/dec.. The electrode also had great stability and lower detection limit.3) Li₃V₂（PO₄）₃, Li₃V_1.8Mg_0.3PO₄)₃ and Li3V1.8Cu0.3（PO₄）₃ were prepared by cabo-thermal reduction method. The LVP-CPE had a Nernst response to Li+. LVP（Mg）-CPE and LVP（Cu）-CPE also exhibited good linear response to Li+.4) Na₃V₂（PO₄）₃ was prepared by cabothermal reduction method too, which was used as active material of Na+ ISE. With optimum composition exhibited nearly linear response of 50.8 m V/dec. and detection limit of 3.16×10-5 mol/L.These alkali metal-selective electrodes based on reversible deintercalation materials have good response and anti-jamming capability which indicate that the reversible deintercalation material has great application and potential markets.