Key Laboratory of Automobile Materials (Jilin University), Ministry of Education, and School of Materials Science and Engineering, Jilin University, 130022, Changchun, China.
Nat Commun. 2019 Sep 20;10(1):4292. doi: 10.1038/s41467-019-12274-7.
Aqueous rechargeable microbatteries are promising on-chip micropower sources for a wide variety of miniaturized electronics. However, their development is plagued by state-of-the-art electrode materials due to low capacity and poor rate capability. Here we show that layered potassium vanadium oxides, KVO·nHO, have an amorphous/crystalline dual-phase nanostructure to show genuine potential as high-performance anode materials of aqueous rechargeable potassium-ion microbatteries. The dual-phase nanostructured KVO·nHO keeps large interlayer spacing while removing secondary-bound interlayer water to create sufficient channels and accommodation sites for hydrated potassium cations. This unique nanostructure facilitates accessibility/transport of guest hydrated potassium cations to significantly improve practical capacity and rate performance of the constituent KVO·nHO. The potassium-ion microbatteries with KVO·nHO anode and KMnO·nHO cathode constructed on interdigital-patterned nanoporous metal current microcollectors exhibit ultrahigh energy density of 103 mWh cm at electrical power comparable to carbon-based microsupercapacitors.
水系可充式微电池作为各种小型化电子产品的片上微电源，具有广阔的应用前景。然而，由于目前的电极材料容量低、倍率性能差，其发展受到了阻碍。在这里，我们展示了层状钾钒氧化物 KVO·nHO 具有非晶/晶态双相纳米结构，有望成为高性能水系可充式钾离子微电池的阳极材料。双相纳米结构的 KVO·nHO 在去除次级结合层间水的同时保持较大的层间距，为水合钾阳离子创造了足够的通道和容纳位置。这种独特的纳米结构便于客体水合钾阳离子的可及性/传输，从而显著提高了组成 KVO·nHO 的实际容量和倍率性能。在叉指图案化纳米多孔金属电流微集电器上构建的以 KVO·nHO 为阳极和 KMnO·nHO 为阴极的钾离子微电池，在与基于碳的微超级电容器相当的电功率下，具有超高的能量密度 103 mWh cm。
