Study On Primary Lithium Batteries With High Energy Density

High energy density is the eternal theme for batteries.In a conventional Li battery,the electrolyte mainly plays the role of conducting lithium ion without contribution to the cell capacity.However,the expendable nature of primary batteries makes the electrolyte have multi functions possibility:as the ionic conductor and also as the electrode.The application of multifunctional electrolyte is an effective method to improve the energy density of primary batteries.In this paper,we successfully introduce the concept of multifunctional electrolyte into the high-energy-density Li/CF_x batteries,aiming to obtain even higher energy density primary lithium battery systems.Ethylene sulfite?ES?is explored as a novel soluble liquid cathode for Li primary battery for the first time.The electrochemical reduction potential,discharge specific capacity of ES are investigated by linear sweep voltammetry?LSV?and galvanostatic discharge test.The electrochemical reaction mechanism of ES is investigated by scanning electron microscopy?SEM?,density function theory?DFT?and X-ray photoelectron spectroscopy?XPS?analysis.To further improve the specific energy of Li/CF_x batteries,using ES as the multifunctional electrolyte:as both the soluble liquid cathode and the electrolyte co-solvent,a new type of Li/ES/CF_x primary battery with dual cathode materials is designed and explored.In this new battery,discharge capacity can be consecutively contributed by solid electrode material and soluble liquid cathode.Two kinds of batteries,from coins to soft packages,are carried out to confirm the superiority of this new battery.Improvement in discharge capacity and specific energy are observed for both the coin-type and pouch Li/ES/CF_x primary cells.Li/ES/CF_x soft package batteries are assembled,achieving a energy of 9292 Wh,which is 15%higher than conventional Li/CF_x battery.Li_1.3Al_0.3Ti_1.7?PO₄?₃?LATP?has been successfully synthesized via a modified Pechini method.The microstructure and crystal structures of prepared LATP are investigated by using of scanning electron microscopy?SEM?and powder X-ray diffraction?XRD?,respectively.The results show that the LATP particles distribute homogeneously and the LATP glass-ceramics have NASICON structure with the space group of R3c,which has 3-dimensional ionic conducting path.The ionic conductivity and electron conductivity are measured by Electrochemical Impedance Spectroscopy?EIS?and potentiostatic polarization method,respectively.The LATP electrolyte pellet with ionic conductivity of 2×10-4 S/cm can be obtained.Additionally,this electrolyte sample has a negligible electronic conductivity.These results imply that the prepared LATP can be considered as one of idea candidates for solid state electrolytes applied in Lithium batteries.We try to build a sustainable consumption solid-state primary lithium battery by using LATP as an multifunctional electrolyte,in which the components of the battery can be continuously consumed as much as possible.A new type of Li/LATP/CF_x dual cathode solid battery is designed,in which LATP serves as both the solid electrolyte and a cathode active material when connected to the electronic conductor on the cathode.An improved capacity would be obtained with the combination of both solid?CF_x?and solid?LATP?cathodes.