Hybrid\nCellular Nanosheets for High-Performance Lithium-Ion\nBattery Anodes

Abstract

We report a simple\nsynthetic method of carbon-based hybrid cellular\nnanosheets that exhibit outstanding electrochemical performance for\nmany key aspects of lithium-ion battery electrodes. The nanosheets\nconsist of close-packed cubic cavity cells partitioned by carbon walls,\nresembling plant leaf tissue. We loaded carbon cellular nanosheets\nwith SnO₂ nanoparticles by vapor deposition method and\ntested the performance of the resulting SnO₂–carbon\nnanosheets as anode materials. The specific capacity is 914 mAh g^–1 on average with a retention of 97.0% during 300 cycles,\nand the reversible capacity is decreased by only 20% as the current\ndensity is increased from 200 to 3000 mA g^–1. In\norder to explain the excellent electrochemical performance, the hybrid\ncellular nanosheets were analyzed with cyclic voltammetry, in situ\nX-ray absorption spectroscopy, and transmission electron microscopy.\nWe found that the high packing density, large interior surface area,\nand rigid carbon wall network are responsible for the high specific\ncapacity, lithiation/delithiation reversibility, and cycling stability.\nFurthermore, the nanosheet structure leads to the high rate capability\ndue to fast Li-ion diffusion in the thickness direction.