In the past years, sodium-ion batteries (SIBs) have attracted much attention due to their potential application in large-scale energy storage. However, for now, it is difficult for anode materials to achieve further practical application. In this work, we designed a sandwich structure in which SnO nanoparticles were entrapped between the layers of reduced graphene oxide (SnO/rGO) via freeze drying. The unique structure can not only offer a 3D carbon network but also relieve volume expansion during discharge/charge processes. When used as an anode material for SIBs, the material exhibits excellent rate capability and stable cycling performance. It can be found that a reversible capacity of 132.3 mA h g⁻¹ can be obtained even at a current density of 5 A g⁻¹. In addition, SnO/rGO shows a charge capacity of 109.5 mA h g⁻¹ with a capacity retention of 70.62% after 1200 cycles at 4 A g⁻¹. When assembled with Na₃V₂(PO₄)₂O₂F (NVPOF) as the cathode, the sodium-ion full cells also display high rate performance, suggesting a reversible capacity of 65.7 mA h g⁻¹ at 20C and an energy density of 138.95 W h kg⁻¹ at −0.1C. The unique structure provides a simple and facile method to achieve high electrochemical performance which is beneficial for developing commercial anode materials for SIBs.

中文翻译：

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一种由市售SnO和还原型氧化石墨烯组成的三明治纳米复合材料，作为钠离子全电池的高级阳极材料

在过去的几年中，钠离子电池（SIB）由于其在大规模能量存储中的潜在应用而备受关注。然而，就目前而言，阳极材料难以实现进一步的实际应用。在这项工作中，我们设计了一种三明治结构，其中SnO纳米颗粒通过冷冻干燥夹在还原的氧化石墨烯（SnO / rGO）层之间。独特的结构不仅可以提供3D碳网络，还可以缓解放电/充电过程中的体积膨胀。当用作SIB的阳极材料时，该材料具有出色的倍率性能和稳定的循环性能。可以发现，即使在电流密度为5 A g ^{-1的情况下，}也可得到132.3 mA hg ^-1的可逆容量。。此外，SnO / rGO在4 A g ^-1下经过1200次循环后的充电容量为109.5 mA hg ^-1，容量保持率为70.62％。当以Na ₃ V ₂（PO ₄）₂ O ₂ F（NVPOF）作为阴极组装时，钠离子全电池还显示出高倍率性能，表明在20C时可逆容量为65.7 mA hg ^-1在-0.1C时为138.95 W h kg ^-1。独特的结构提供了一种简单而又简便的方法来实现高电化学性能，这对于开发用于SIB的商业阳极材料是有利的。