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.

Effect of LiTFSI and LiFSI on Cycling Performance of Lithium Metal Batteries Using Thermoplastic Polyurethane/Halloysite Nanotubes Solid Electrolyte

All-solid-state lithium batteries(ASSLB) are promising candidates for next-generation energy storage devices.Nevertheless,the large-scale commercial application of high energy density AS S LB with the polymer electrolyte still faces challenges.In this study,a thin solid polymer composite electrolyte(SPCE) is prepared through a facile and cost-effective strategy with an infiltration of thermoplastic polyurethane(TPU),lithium salt(LiTFSI or LiFSI),and halloysite nanotubes(HNTs) in a porous framework of polyethylene separator(PE)(TPU-HNTs-LiTFSI-PE or TPU-HNTs-LiFSI-PE).The composition,electrochemical performance,and especially the effect of anions(TFSI-and FSI-) on cycling performance are investigated.The results reveal that the flexible TPU-HNTs-LiTFSI-PE and TPU-HNTs-LiFSI-PE with a thickness of 34 μm exhibit wide electrochemical windows of 4.9 and 5.1 V(vs.Li+/Li) at 60℃,respectively.Reduction in FSI-tends to form more LiF and sulfur compounds at the interface between TPU-HNTs-LiFSI-PE and Li metal anode,thus enhancing the interfacial stability.As a result,cell composed of TPU-HNTs-LiFSI-PE exhibits a smaller increase in interfacial resistance of solid electrolyte interphase(SEI) with a distinct decrease in charge-transfer resistance during cycling.Li|Li symmetric cell with TPU-HNTs-LiFSI-PE could keep its stable overpotential profile for nearly 1300 h with a low hysteresis of approximately39 mV at a current density of 0.1 mA cm-2,while a sudden voltage rise with internal cell impedance-surge signals was observed within 600 h for cell composed of TPU-HNTs-LiTFSI-PE.The initial capacities of NCMITPU-HNTs-LiTFSIPEILi and NCMITPU-HNTs-LiFSI-PEILi cells were 149 and 114 mAh g-1,with capacity retention rates of 83.52% and89.99% after 300 cycles at 0.5 C,respectively.This study provides a valuable guideline for designing flexible SPCE,which shows great application prospect in the practice of ASSLB.

Three-dimensional hierarchical Ca_(3)Co_(4)O_(9) hollow fiber network as high performance anode material for lithium-ion battery

Transition metal oxides have high specific capacity as anode materials for lithium-ion battery.But aggregation of particles and volume expansion during lithiation/delithiation restrict their application.In this work,a three-dimensional hierarchical Ca_(3)Co_(4)O_(9)hollow fiber network assembled by nanosheets is prepared by an electrospinning combined with heat treatment method to overcome these issues and to boost its lithium storage performance.As-synthesized sample possesses excellent cyclic stability(578.6 m A h g^(-1)at 200 m A g^(-1)after 500 cycles)and rate performance(293.5 m A h g^(-1)at 5000 m A g^(-1)),much better than those of commercial Co_(3)O4.Furthermore,the fast kinetics of the three-dimensional Ca_(3)Co_(4)O_(9)hollow fiber network is also confirmed by the variable scan rates CV tests and the EIS measurements,which is dedicated to the specific hierarchical hollow fiber network structure that provides shorter ion transport distances and higher electrical conductivity.This work supplies a universal approach to improve the electrochemical performance of transition metal oxides for lithium ion batteries.

Improving Li Plating Behaviors Through Cu-Sn Alloy-Coated Current Collector for Dendrite-Free Lithium Metal Anodes

Alloy anode with good reversibility of lithium plating/stripping and long cycling stability is considered as promising anode materials.Here,Cu-Sn alloy is used as the substrate for Li deposition to induce the most densely packed arrangement of Li atoms,thus presenting high lithiophilicity and improving Li plating behaviors.The LiFePO4-based full cell with the asprepared dendrite-free Li metal anode retained at 85 mAh g-1 with a high coulombic efficiency of 99.5% after 300 cycles,presenting a capacity retention of 79.4%.This strategy provides a new perspective to structure dendrite-free Li anode for the next-generation high-energy density batteries.

多活性中心Co3O4-CeO2/Co-N-C复合材料作为锌空气电池的优良氧还原催化剂

为了满足新一代金属空气电池对绿色、低成本且具有高氧还原催化活性催化剂的迫切需求,本文通过简便方法制备了具有多活性中心的Co3O4-CeO2/Co-N-C(科琴黑)氧还原催化剂.其中,Co3O4和CeO2纳米颗粒均匀地固定在Co、N共掺杂的碳载体表面Co3O4-CeO2/Co-N-C在旋转圆盘电极测试中的半波电位与Pt/C接近.以Co3O4-CeO2/Co-N-C作为阴极催化剂的锌空气电池可以在20 mA cm^-2下提供728 mA h g^-1的高比容量并能够维持稳定的放电电压.其优异的催化性能主要归功于Co3O4、CeO2和Co-N-C之间的协同作用、高导电性和大比表面积.Co3O4-CeO2/Co-N-C催化剂具有催化活性高、环境友好、合成工艺简单等优点,在金属空气电池中具有广阔的应用前景.