材料科学
电解质
阴极
阳极
化学工程
聚合物
电池(电)
准固态
固态
电极
离子电导率
分离器(采油)
纳米技术
快离子导体
复合数
电化学
聚合物电解质
复合材料
化学
色素敏化染料
功率(物理)
物理化学
工程类
物理
量子力学
作者
Jiulin Hu,Keyi Chen,Zhenguo Yao,Chilin Li
标识
DOI:10.1016/j.scib.2020.11.017
摘要
Pursuing all-solid-state lithium metal batteries with dual upgrading of safety and energy density is of great significance. However, searching compatible solid electrolyte and reversible conversion cathode is still a big challenge. The phase transformation at cathode and Li deformation at anode would usually deactivate the electrode–electrolyte interfaces. Herein, we propose an all-solid-state Li-FeF 3 conversion battery reinforced by hierarchical microsphere stacked polymer electrolyte for the first time. This g-C 3 N 4 stuffed polyethylene oxide (PEO)-based electrolyte is lightweight due to the absence of metal element doping, and it enables the spatial confinement and dissolution suppression of conversion products at soft cathode-polymer interface, as well as Li dendrite inhibition at filler-reinforced anode-polymer interface. Two-dimensional (2D)-nanosheet-built porous g-C 3 N 4 as three-dimensional (3D) textured filler can strongly cross-link with PEO matrix and LiTFSI (TFSI: bistrifluoromethanesulfonimide) anion, leading to a more conductive and salt-dissociated interface and therefore improved conductivity (2.5 × 10 –4 S/cm at 60 °C) and Li + transference number (0.69). The compact stacking of highly regular robust microspheres in polymer electrolyte enables a successful stabilization and smoothening of Li metal with ultra-long plating/striping cycling for at least 10,000 h. The corresponding Li/LiFePO 4 solid cells can endure an extremely high rate of 12 C. All-solid-state Li/FeF 3 cells show highly stabilized capacity as high as 300 mAh/g even after 200 cycles and of ~200 mAh/g at extremely high rate of 5 C, as well as ultra-long cycling for at least 1200 cycles at 1 C. High pseudocapacitance contribution (>55%) and diffusion coefficient (as high as 10 –12 cm 2 /s) are responsible for this high-rate fluoride conversion. This result provides a promising solution to conversion-type Li metal batteries of high energy and safety beyond Li-S batteries, which are difficult to realize true “all-solid-state” due to the indispensable step of polysulfide solid–liquid conversion.
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