Hierarchically Porous, Ultrathick, "Breathable" Wood-Derived Cathode for Lithium-Oxygen Batteries
Hierarchically Porous, Ultrathick, "Breathable" Wood-Derived Cathode for Lithium-Oxygen Batteries
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DOI：
10.1002/aenm.201701203
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发表时间：
2018-02-05
影响因子：
27.8
通讯作者：
Hu, Liangbing
中科院分区：
文献类型：
--
作者：
Song, Huiyu;Xu, Shaomao;Hu, Liangbing
在这项工作中，开发了一种用于高性能 Li-O-2 电池的分层多孔和超厚“透气”木质阴极。从碳化和活化的木材（表示为 CA-wood）中获得的 3D 碳基质可用作超导集电器和容纳催化剂的理想多孔主体。钌 (Ru) 纳米颗粒均匀地锚定在排列的微通道（表示为 CA-wood/Ru）的多孔壁上。碳基质内排列整齐的开放微通道有助于氧气的畅通无阻的扩散。此外，微通道壁上的分级孔可以很容易地被电解质浸渍，形成电解质的连续供应。结果，形成了许多理想的三相活性位点，电解质、氧气和催化剂在微通道的多孔壁上积聚。受益于众多平衡良好的三相活性位点，采用CA-wood/Ru正极（厚度：约700μm）组装的Li-O-2电池在0.1 mA cm(-2)下表现出8.58 mA h cm(-2)的高比面积容量。此外，通过使用厚度约为3.4 mm的超厚CA-wood/Ru阴极，面积容量可以进一步增加至56.0 mA h cm(-2)。简便的超厚木质正极可以应用于其他正极，以在不牺牲电化学性能的情况下实现超高的面积容量。
In this work, a hierarchically porous and ultrathick ''breathable'' wood-based cathode for high-performance Li-O-2 batteries is developed. The 3D carbon matrix obtained from the carbonized and activated wood (denoted as CA-wood) serves as a superconductive current collector and an ideal porous host for accommodating catalysts. The ruthenium (Ru) nanoparticles are uniformly anchored on the porous wall of the aligned microchannels (denoted as CA-wood/Ru). The aligned open microchannels inside the carbon matrix contribute to unimpeded oxygen gas diffusion. Moreover, the hierarchical pores on the microchannel walls can be facilely impregnated by electrolyte, forming a continuous supply of electrolyte. As a result, numerous ideal triphase active sites are formed where electrolyte, oxygen, and catalyst accumulate on the porous walls of microchannels. Benefiting from the numerous well-balanced triple-phase active sites, the assembled Li-O-2 battery with the CA-wood/Ru cathode (thickness: approximate to 700 mu m) shows a high specific area capacity of 8.58 mA h cm(-2) at 0.1 mA cm(-2). Moreover, the areal capacity can be further increased to 56.0 mA h cm(-2) by using an ultrathick CA-wood/Ru cathode with a thickness of approximate to 3.4 mm. The facile ultrathick wood-based cathodes can be applied to other cathodes to achieve a super high areal capacity without sacrificing the electrochemical performance.