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Abstract：
3D electrode design is normally opted for multiple advantages, however, instability/detachment of active material causes the pulverization and degradation of the structure, and ultimately poor cyclic stability. Here, a dually protected, highly compressible, and freestanding anode is presented for sodium-ion batteries, where 3D carbon nanotube (CNT) sponge is decorated with homogeneously dispersed CoSe2 nanoparticles (NPs) which are protected under carbon overcoat (CNT/CoSe2/C). The 3D CNT sponge delivers enough space for high mass loading while providing high mechanical strength and faster conduction pathway among the NPs. The outer amorphous carbon overcoat controls the formation of solid electrolyte interphase film by avoiding direct contact of CoSe2 with electrolyte, accommodates large volume changes, and ultimately enhances the overall conductivity of cell and assists in transmitting electron to an external circuit. Moreover, the hybrid can be densified up to 11-fold without affecting its microstructure that results in ultrahigh areal mass loading of 17.4 mg cm-2 and an areal capacity of 7.03 mAh cm-2 along with a high gravimetric capacity of 531 mAh g-1 at 100 mA g-1. Thus, compact and smart devices can be realized by this new electrode design for heavy-duty commercial applications.
摘要：
3D电极设计通常选择多种优势，然而,活性材料的不稳定性/脱离导致结构的粉碎和降解，最终循环稳定性差。这里,一个双重保护，高度可压缩，提出了钠离子电池的独立式阳极，其中3D碳纳米管（CNT）海绵用均匀分散的CoSe2纳米颗粒（NP）装饰，这些纳米颗粒在碳外涂层（CNT/CoSe2/C）下受到保护。3DCNT海绵为高质量负载提供足够的空间，同时在NP之间提供高机械强度和更快的传导途径。外部无定形碳外涂层通过避免CoSe2与电解质的直接接触来控制固体电解质界面膜的形成，适应大的体积变化，并最终增强电池的整体导电性，并有助于将电子传输到外部电路。此外，该杂化物可以致密化11倍，而不会影响其微观结构，从而导致17.4mgcm-2的超高面积质量负载和7.03mAhcm-2的面积容量以及531mAhg-1的高重量容量在100mAg-1。因此，紧凑型和智能设备可以通过这种用于重型商业应用的新电极设计来实现。
