基于无毒的富含地球元素的高容量金属氧化物作为锂离子电池(LIBs)的高级阳极提供了独特的机会。但是它们经常遭受大的体积膨胀,颗粒粉碎,广泛的副反应,和快速降解在循环过程中。这里,报道了一种简单的合成方法来构建无定形硼酸盐涂层网络,这稳定了用于高能量密度半固态双极LIB的转换型氧化铁阳极。纳米硼酸盐包覆的氧化铁阳极具有高振实密度(1.6gcm-3),高容量(710mAhg-1在0.5-3.0V之间,vsLi/Li+),良好的倍率性能(在50C时为200mAhg-1),和出色的循环稳定性(在5Ag-1的情况下,在1,000次循环中≈100%的容量保留)。当与高压阴极LiCoO2配对时,它使Cu集流器无袋型经典双极全电池具有高电压(7.6V,具有两个堆叠层),实现高能量密度(≈350Whkg-1),出色的功率密度(≈6,700Wkg-1),和延长的循环寿命(在2℃下2,000次循环后75%的容量保持率),优于国家的最先进的高功率LIB使用Li4Ti5O12阳极。纳米级聚阴离子样涂层的设计和方法可应用于其他金属氧化物电极材料,以及其他电化学材料和器件。
High-capacity metal oxides based on non-toxic earth-abundant elements offer unique opportunities as advanced anodes for lithium-ion batteries (LIBs). But they often suffer from large volumetric expansion, particle pulverization, extensive side reactions, and fast degradations during cycling. Here, an easy synthesis method is reported to construct amorphous borate coating network, which stabilizes conversion-type iron oxide anode for the high-energy-density semi-solid-state bipolar LIBs. The nano-borate coated iron oxide anode has high tap density (1.6 g cm-3 ), high capacity (710 mAh g-1 between 0.5 - 3.0 V, vs Li/Li+ ), good rate performance (200 mAh g-1 at 50 C), and excellent cycling stability (≈100% capacity resention over 1,000 cycles at 5 A g-1 ). When paired with high-voltage cathode LiCoO2 , it enables Cu current collector-free pouch-type classic and bipolar full cells with high voltage (7.6 V with two stack layers), achieving high energy density (≈350 Wh kg-1 ), outstanding power density (≈6,700 W kg-1 ), and extended cycle life (75% capacity retention after 2,000 cycles at 2 C), superior to the state-of-the-art high-power LIBs using Li4 Ti5 O12 anode. The design and methodology of the nanoscale polyanion-like coating can be applied to other metal oxides electrode materials, as well as other electrochemical materials and devices.