Niobium tungsten oxides for high-rate lithium-ion energy storage
Niobium tungsten oxides for high-rate lithium-ion energy storage
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DOI：
10.1038/s41586-018-0347-0
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发表时间：
2018-07-26
期刊：
影响因子：
64.8
通讯作者：
Grey, Clare P.
中科院分区：
文献类型：
--
作者：
Griffith, Kent J.;Wiaderek, Kamila M.;Grey, Clare P.
锂离子电池的最大功率输出和最短充电时间取决于离子和电子传输。电化学活性颗粒内的离子扩散通常代表对电池可充电和放电的速率的基本限制。为了补偿相对缓慢的固态离子扩散并实现高功率和快速充电，活性颗粒经常被减小到纳米尺寸，这损害了体积堆积密度、成本、稳定性和可持续性。作为替代纳米尺度，在这里，我们表明，两个复杂的铌钨氧化物-Nb 16 W5 O 55和Nb 18 W16 O 93，采用晶体剪切和青铜样结构，分别可以插入大量的锂在高速率，即使当铌钨氧化物颗粒的尺寸是微米的顺序。在这两种结构中的锂离子扩散系数的测量揭示了室温值比典型的电极材料如Li 4 Ti 5 O 12和LiMn 2 O 4高几个数量级。多电子氧化还原，缓冲体积膨胀，拓扑挫败铌/钨多面体的安排和快速固态锂传输导致极高的体积容量和倍率性能。能够在几分钟内实现微米级颗粒锂化的非常规材料和机制对高功率应用、快速充电设备、全固态储能系统、电极设计和材料发现具有重要意义。
The maximum power output and minimum charging time of a lithium-ion battery depend on both ionic and electronic transport. Ionic diffusion within the electrochemically active particles generally represents a fundamental limitation to the rate at which a battery can be charged and discharged. To compensate for the relatively slow solid-state ionic diffusion and to enable high power and rapid charging, the active particles are frequently reduced to nanometre dimensions, to the detriment of volumetric packing density, cost, stability and sustainability. As an alternative to nanoscaling, here we show that two complex niobium tungsten oxides-Nb16W5O55 and Nb18W16O93, which adopt crystallographic shear and bronze-like structures, respectively-can intercalate large quantities of lithium at high rates, even when the sizes of the niobium tungsten oxide particles are of the order of micrometres. Measurements of lithium-ion diffusion coefficients in both structures reveal room-temperature values that are several orders of magnitude higher than those in typical electrode materials such as Li4Ti5O12 and LiMn2O4. Multielectron redox, buffered volume expansion, topologically frustrated niobium/tungsten polyhedral arrangements and rapid solid-state lithium transport lead to extremely high volumetric capacities and rate performance. Unconventional materials and mechanisms that enable lithiation of micrometre-sized particles in minutes have implications for high-power applications, fast-charging devices, all-solid-state energy storage systems, electrode design and material discovery.