Structure Design,Synthesis And Application Of Porous Solid Electrolyte

With the rapid development of electronic science and technology,more and more intelligent electronic devices have been introduced into the drug delivery system to constitute the electronic drug delivery system.This new electronic drug delivery system has made great contributions to the development of the medical industry.Electronic drug delivery systems have become an unstoppable trend due to their ability to deliver precise specific doses,reduce side effects,and thus improve drug treatment outcomes.However,the advanced electronic drug delivery system is still in the development stage,and there are still many areas to be improved.Therefore,in order to solve the problems of insufficient power storage and limited battery life in electronic drug delivery system,it is important to develop and design miniaturized,high energy density and safe batteries.As one of the most important components in all solid lithium metal batteries,solid electrolyte is the key to promote the commercialization of all solid lithium metal batteries.The porous solid electrolyte,which is composed of porous materials and polymer matrix,is considered as the most promising solid electrolyte due to its easy processing,high flexibility,good surface contact,strong mechanical properties and stable electrochemical properties.However,it is relatively rare to systematically study porous solid electrolyte based on organic and inorganic porous materials,especially the effect of porous materials loaded with obvious surface polarity on solid electrolyte electrochemistry.In addition,studies on the design of porous solid electrolytes with topological structures are also rare,so it is innovative to systematically study the effects of organic and inorganic porous materials on the properties of solid electrolytes.In this paper,we designed two kinds of porous solid electrolyte systems,from the synthesis of new structures to the characterization and application of their properties,and carried out a systematic study.Firstly,we selected organic ligands containing-NH₂ and-NO₂ to synthesize different functionalized MOFs as porous fillers of the porous solid electrolyte.The modified MOFs were used to regulate the structure and polarity of the pores in the porous solid electrolyte,so as to explore the deposition behavior of lithium ions by the polarity of the pores.Cyclic voltammetry showed that the nitro functionalized porous solid electrolyte（UIO-66-NO₂@P）had been oxidized slowly at 3.0 V,while the amine functionalized porous solid electrolyte（UIO-66-NH₂@P）rapidly formed a passivation layer and stabilized in subsequent cycles,extending the safe voltage to about4.5 V.And the average ionic conductivity of UIO-66-NH₂@P can be as high as 3.56×10^-4 S cm^-1 through the test and calculation of electrochemical impedance data.In contrast,the average ionic conductivity of UIO-66-NO₂@P was only 2.68×10^-4 S cm^-1.In Li/Li battery lithium stripping/sedimentation tested,UIO-66-NH₂@P showed good lithium battery deposit stability,under the current density of 0.1 m A cm^-2 stripping deposit after1500 hours not showed signs of lithium ion instability of electrodeposition,polarization voltage remained at about 40 mv,greatly inhibited the growth of the lithium dendrite.The UIO-66-NO₂@P porous solid electrolyte with the opposite electronic effect exhibited an unstable voltage response immediately after the first few cycles and short-circuited after100 hours of operation.Li/LFP full cells with UIO-66-NH₂@P at 60°C afforded the initial discharge specific capacity of 164 m Ah g^-1,and those of UIO-66-NO₂@P and the PEO were 147.2 and 150.6 m Ah g^-1,and UIO-66-NH₂@P after a 110 cycle can still keep high coulomb efficiency and discharge specific capacity(99%,117 m Ah g^-1),and the PEO solid electrolyte in circular 100 laps after discharge specific capacity quickly fell by60%.UIO-66-NO₂@P only showed 50%specific capacity after 50 cycles,and completely short-circuited after 100 cycles.The continuous rate charge-discharge cycle test showed that UIO-66-NH2@P can still maintain a high capacity of 154 m Ah g^-1 at 0.2 C,but this faster current density had reduced the capacity of the PEO electrolyte to about 87 m Ah g^-1.Through the battery cycle test,it was proved that different structure designs have different effects on the battery performance.Secondly,we investigated the effect of topological porous structure on the interfacial stability and electrical conductivity of lithium ions through the synthesis of fluorine-containing star hyperbranched porous solid electrolyte based on functionalized nano-POSS.Based on different temperature and different molecular weight PEGMA POSS porous solid electrolyte of AC impedance test showed that the POSS-HFBMA-L-PEGMA（950）-B at 30°C showed a small impedance value,than PEGMA molecular weight 500 porous solid electrolyte decreased in two orders of magnitude,that increase flexible ether chain segments to make interface and better compatibility,which is based on porous POSS hyperbranched structure design can be obviously improved by increase the molecular weight of crystalline.As temperatures rise,POSS-HFBMA-L-PEGMA（950）-B at 70°C,bulk resistance can be reduced to 109?.The electrical conductivity of POSS-HFBMA-L-PESMA（950）-B was increased by an order of magnitude compared with POSS-HFBMA-L-PESMA（500）-B,reaching 2.43×10^-4 S cm^-1 at 70°C,and the migration number was also slightly higher than that of POSS-HFBMA-L-PESMA（500）-B.In summary,porous solid electrolytes have excellent electrochemical properties,among which different structural designs play a crucial role in improving electrical conductivity and interface compatibility.Therefore,this also brings new ideas for the structural design of new solid electrolytes.