Promises and challenges of tin-based compounds as anode materials for lithium-ion batteries

Lithium-ion batteries (LIBs) with high performance have played indispensable roles in today's portable electronics enabling the highly mobile society with uninterrupted connection; however, their development has lagged far behind the rapid advancement of other technologies including electronic devices and electrical vehicles. The search for better energy storage devices is the investigation of materials with high specific capacity, high-rate capability, and long lasting performance. For LIBs, it is the search for cathode and anode materials with large lithium-ion storage capacity, appropriate charge-discharge voltage, good mass and charge transfer property, and long cyclic stability, in addition to abundance and low processing cost. The common anode material used in current commercial LIBs is graphite, whose theoretical capacity is only 372 mA h g(-1), much lower than those of silicon, germanium, and tin-based compounds (TBCs). Tin-based compounds have drawn much attention in the field of LIBs because of their advantages in terms of low cost for synthesis and rich source compared with silicon and germanium. However, TBCs as anodes for LIBs suffer from two serious drawbacks: the pulverisation of TBCs arising from the huge volume expansion and contraction change during lithiation/delithiation, and the relatively low Coulombic efficiency owing to the irreversible formation of solid electrolyte interphase (SEI) films, Li2O or Li2S. This review paper summarises and analyses a variety of strategies and synthesis methods used to design and create novel nano-and microstructures of TBCs with desired chemical compositions to circumvent above two issues. The discussion focuses mainly on the relationships between various nano-and microstructures and lithium-ion storage properties of TBCs and tries to offer some opinions about the possible future directions of the practical application and research on TBCs as anodes for LIBs.