3D Honeycomb Architecture Enables a High‐Rate and Long‐Life Iron (III) Fluoride–Lithium Battery
3D Honeycomb Architecture Enables a High‐Rate and Long‐Life Iron (III) Fluoride–Lithium Battery
复制标题
DOI：
10.1002/adma.201905146
复制
发表时间：
2019-09
影响因子：
29.4
通讯作者：
Feixiang Wu;V. Srot;Shuangqiang Chen;S. Lorger;P. V. van Aken;J. Maier;Yan Yu
中科院分区：
文献类型：
--
作者：
Feixiang Wu;V. Srot;Shuangqiang Chen;S. Lorger;P. V. van Aken;J. Maier;Yan Yu
金属氟化物-锂电池具有潜在的高能量密度，甚至比锂硫电池更高，被视为下一代轻型和低成本充电电池的非常有前途的候选者。然而，到目前为止，金属氟化物正极存在电子传导性差、反应动力学迟缓和副反应导致的高电压滞后、倍率能力差以及循环后容量迅速下降的问题。在这里，据报道，通过简单的方法合成具有3D蜂窝结构的FeF3@C复合材料可以克服这些问题。FeF3纳米粒子(10-50 nm)均匀地嵌入在3D蜂窝碳骨架中，其中蜂窝壁和六角形通道分别为快速电子和锂离子的扩散提供了足够的路径。结果表明，所制备的3D蜂窝状FeF_3@C复合正极，即使具有2.2和5.3 mg cm−_3的高面负载量，也能在1000次循环内提供前所未有的高达100C的倍率容量和显著的循环稳定性，在不同的C速率下，在200次循环内容量保持率为95%-100%，在1000次循环内的≈保持率为85%。结果表明，3D蜂窝结构是一种功能强大的转换型金属氟化物的复合材料设计，可以在金属氟化物-锂电池中实现优异的电化学性能。
Metal fluoride–lithium batteries with potentially high energy densities, even higher than lithium–sulfur batteries, are viewed as very promising candidates for next‐generation lightweight and low‐cost rechargeable batteries. However, so far, metal fluoride cathodes have suffered from poor electronic conductivity, sluggish reaction kinetics and side reactions causing high voltage hysteresis, poor rate capability, and rapid capacity degradation upon cycling. Herein, it is reported that an FeF3@C composite having a 3D honeycomb architecture synthesized by a simple method may overcome these issues. The FeF3 nanoparticles (10–50 nm) are uniformly embedded in the 3D honeycomb carbon framework where the honeycomb walls and hexagonal‐like channels provide sufficient pathways for the fast electron and Li‐ion diffusion, respectively. As a result, the as‐produced 3D honeycomb FeF3@C composite cathodes even with high areal FeF3 loadings of 2.2 and 5.3 mg cm−2 offer unprecedented rate capability up to 100 C and remarkable cycle stability within 1000 cycles, displaying capacity retentions of 95%–100% within 200 cycles at various C rates, and ≈85% at 2C within 1000 cycles. The reported results demonstrate that the 3D honeycomb architecture is a powerful composite design for conversion‐type metal fluorides to achieve excellent electrochemical performance in metal fluoride–lithium batteries.