Sn accommodation in tunable-void and porous graphene bumper for high-performance Li- and Na-ion storage

Abstract Nanoscale microstructure designing is playing an important role in improving the performance of electrode materials of an electrochemical battery. The Sn based anode is among the very high-capacity but less-stable materials, and has been used mostly for anode of the Li-ion battery with unsatisfactory performance. In this work, we design a new type of 3D porous graphene and nano-Sn composite (Sn/Void@G) by simple one-step annealing of graphene oxide, polystyrene spheres and stannic chloride for both high performance Li- and Na-ion battery anodes. More importantly, the 3D porous graphene formed tunable micro-nano void as a highly efficient “bumper” to accommodate the large volume expansion of nano-Sn particles. As results, the discharge specific capacity of the Sn/Void@G, anode still remains 45.3% while the charge-discharge current is increased 50 times, and the capacity is more than 400 mAh g −1 after 500 cycles at 5C rate. For Na storage, the integrated anodes deliver the Na storage capacity of 786.1 mAh/g at 0.1C rate and the capacity of more than 340 mAh/g after 800 cycles at 2C rate. The present result on Li and Na ion battery may pave the way to next generation high power and energy density batteries.