| Under the demands of environmental protection and low-carbon lifestyle,the trend of replacing traditional fuel vehicles with new energy vehicles has become irreversible.Among new energy vehicles,electric vehicle?EVs?,as an important one,has attracted extensive attention and been researched in recent years.There are two main challenges in the development of EVs:driving range and safety.Lithium-air battery,as one of“Beyond Lithium-ion”Batteries,has a theoretical energy density,regardless of mass of oxygen,up to 11430 Wh kg-1,due to using lithium metal with a large specific capacity and low reversible potential as the negative electrode,and oxygen in air as the positive active material.Moreover,compared with traditional liquid electrolyte,solid electrolyte does not contain flammable and volatile components,which can greatly improve the safety of battery.Therefore,solid-state lithium-air batteries are expected to be the power battery of EVs in the future.However,many problems of solid-state lithium-air batteries remains to be solved,such as chemical stability between lithium metal and solid electrolyte,large interfacial resistance,strict requirements for cells forming technical and poor repeatability.In this work,based on garnet solid electrolyte materials and lithium-air battery,related researches are done for compatibility of solid-state interface and integration of solid-state batteries,and some results are gotten,as follows.?1?Noncovalent interactions between the cations of an ammonium ionic liquid and both solid electrolytes are introduced.The ionic liquids-based electrolytes?ILE?are solidified on Li6.40La3Zr1.40Ta0.60O12?LLZTO?nanoparticles and gelated by multi-wall carbon nanotubes?MWCNTs?,respectively,to construct LLZTO@ILE quasi-solid-state electrolyte?QSSE?films and MWCNTs-LLZTO/ILE gel cathode?GC?films.A facile strategy of roll forming is proposed to construct integrated quasi-solid lithium oxygen battery via interface integration of quasi-solid electrolyte and gel anode.The QSSE exhibits a high ionic conductivity of 1.71×10-3 S cm-1 at 60°C,high Li-ion transference number of 0.56,broad electrochemical window of4.8 V and good thermal stability.The GC shows an outstanding compatibility with QSSE.Because of compatibility of GC and QSSE,A Quasi-solid-state Li-O2 batteries show a low total interfacial resistance?87?cm2?,and excellent reversible cycles?70 cycles?with low charge overpotential?<0.44 V?and quite high electrical energy efficiency?>70%?at60°C and 200 mA g-1.These results indicate that the interface integration based on the noncovalent interaction of cations in ionic liquids may be an effective approach to solve the solid-solid interface issue in solid state energy storage devices.?2?On the basis of high-density garnet-type LLZTO thin sheet electrolytes fabricated by a tape-casting method combined with liquid-phase sintering,the integrated solid lithium air battery is constructed through interface regulation of nickel oxide?NiO?at the interface of lithium anode/electrolyte and the design of high-efficiency oxygen cathode supported by LAGP electrolyte.The resultant sheets show a thickness of200?m and a relative density of 99%.Electrochemical measurement results show that the sheets exhibit an ionic conductivity of 5.2×10-4 S cm-1 at 30°C and good chemical and electrochemical stability against Li metal.The Li/LLZTO interface impedance is reduced from 2250?cm2 to 275?cm2 owing to Ni/Li2O crosslinked composite formed through conversion reaction of NiO with molten Li metal,which improved the interface stability in lithium depositing/stripping.Namely,high critical current density of 0.8 mA cm-2 and stability of 400 h cycle are obtained in Li/NiO-LLZTO-NiO/Li symmetry battery.The porous support prepared by the template method with PMMA:LAGP weight ratio of 1:2 has higher porosity,which benefits the loading of activated carbon materials and the improvement of specific energy density of solid-state lithium-air battery.Based on LLZTO sheets,all-solid-state Li/NiO-LLZTO/LAGP-C lithium-air battery assembled by the interface regulation and construction of porous oxygen positive electrode has good electrochemical performance after,which lays a preliminary foundation for runing lithium oxygen battery in the air. |
PDF Full Text Request