Easy synthesis of multi-shelled ZnO hollow spheres and their conversion into hedgehog-like ZnO hollow spheres with superior rate performance for lithium ion batteries

Abstract

Herein, uniform multi-shelled ZnO hollow spheres were synthesized, especially hedgehog-like and triple-shelled ZnO hollow spheres were synthesized for the first time by a simple hydrothermal method capable of controlling the number of internal multishells, which are achieved by controlling the calcination process. Used as anodes for lithium ion batteries, the hedgehog-like ZnO hollow spheres show excellent rate capacity, good cycling performance, and high initial specific capacity. A superior capacity, up to 109 mAh g−1 with minimal irreversible capacity (i.e., coulomb efficiency of 99.1%) after 100 cycles is achieved at a current rate of 100 mA g−1, and a capacity of 98.8 mAh g−1 is obtained at a current rate of 1 A g−1. However, a high discharge of 253.6 mA h g−1 for the hedgehog-like ZnO hollow spheres can still be achieved when the current rate is reduced back to 100 mA g−1.