The critical role of inorganic nanofillers in solid polymer composite electrolyte for Li+transportation

Compared with commercial lithium batteries with liquid electrolytes,all-solidstate lithium batteries(ASSLBs)possess the advantages of higher safety,better electrochemical stability,higher energy density,and longer cycle life;therefore,ASSLBs have been identified as promising candidates for next-generation safe and stable high-energy-storage devices.The design and fabrication of solid-state electrolytes(SSEs)are vital for the future commercialization of ASSLBs.Among various SSEs,solid polymer composite electrolytes(SPCEs)consisting of inorganic nanofillers and polymer matrix have shown great application prospects in the practice of ASSLBs.The incorporation of inorganic nanofillers into the polymer matrix has been considered as a crucial method to achieve high ionic conductivity for SPCE.In this review,the mechanisms of Li+transport variation caused by incorporating inorganic nanofillers into the polymer matrix are discussed in detail.On the basis of the recent progress,the respective contributions of polymer chains,passive ceramic nanofillers,and active ceramic nanofillers in affecting the Li+transport process of SPCE are reviewed systematically.The inherent relationship between the morphological characteristics of inorganic nanofillers and the ionic conductivity of the resultant SPCE is discussed.Finally,the challenges and future perspectives for developing high-performance SPCE are put forward.This review aims to provide possible strategies for the further improvement of ionic conductivity in inorganic nanoscale filler-reinforced SPCE and highlight their inspiration for future research directions.

Boosting fast interfacial Li^(+)transport in solid-state Li metal batteries via ultrathin Al buffer layer

Na superionic conductor(NASICON)-type Li_(1.5)Al_(0.5)Ge_(0.5)P_(3)O_(12)(LAGP)solid state electrolytes(SSEs)have attracted significant interests thanks to the prominent ionic conductivity(>10^(–4)S·cm^(–1))at room temperature and superb stability in air.Unfortunately,its application has been hindered by the lithium dendrites and the intrinsic interfacial instability of LAGP towards metallic Li,etc.Herein,by magnetron sputtering(MS),an ultrathin Al film is deposited on the surface of the LAGP pellet(Al-LAGP).By in-situ alloying reaction,the spontaneously formed LiAl buffer layer inhibits the side reaction between LAGP SSEs and Li metal,induces the uniform distribution of interfacial electric field as well.Density functional theory(DFT)calculations demonstrate that the LiAl alloy surface promotes the diffusion of lithium atoms due to the lower energy barrier,thereby inhibiting the formation of lithium dendrites.Consequently,the Li/Al-LAGP-Al/Li symmetric cells show a low resistance of 210Ωand a durable lifespan over 1,200 h at a high current density of 0.1 mA·cm^(-2).Assembled all solid state lithium metal batteries(ASSLMBs)with LiFePO_(4)(LFP)cathode significantly improve cycle stability and rate performance,proving a promising stabilization strategy towards the NASIOCN type electrolyte/anode interface in solid state Li metal batteries.

Recent progress of composite solid polymer electrolytes for all-solid-state lithium metal batteries

In comparison with lithium-ion batteries(LIBs)with liquid electrolytes,all-solid-state lithium batteries(ASSLBs)have been considered as promising systems for future energy storage due to their safety and high energy density.As the pivotal component used in ASSLBs,composite solid polymer electrolytes(CSPEs),derived from the incorporation of inorganic fillers into solid polymer electrolytes(SPEs),exhibit higher ionic conductivity,better mechanical strength,and superior thermal/electrochemical stability compared to the single-component SPEs,which can significantly promote the electrochemical performance of ASSLBs.Herein,the recent advances of CSPEs applied in ASSLBs are presented.The effects of the category,morphology and concentration of inorganic fillers on the ionic conductivity,mechanical strength,electrochemical window,interfacial stability and possible Li+transfer mechanism of CSPEs will be systematically discussed.Finally,the challenges and perspectives are proposed for the future development of high-performance CSPEs and ASSLBs.