Lithium ion battery (LIB) with high energy and power densities are actively investigated to enhance the competitiveness and extensive development of electric vehicles (EVs) and energy storage system (ESS), and for facilitating novel portable devices. The energy density of a battery is primarily determined by the charge-discharge capacities of the electrode materials and the operating potential of the battery. Due to the low theoretical capacity of graphite (372 mAhg-1 for LiC6), the commercialized anode material for LIBs, development of alternative anode materials for LIBs is strongly required for future applications. Certain metals and metalloids that alloy with lithium is particularly promising, such as Sn and Sb which both show several times higher energy densities than that of graphite (e.g. 993 mAhg-1 for Li4.4Sn; 660 mAhg-1 for Li3Sb). The choice of the SnSb from several synergistic effects between the Sn and Sb: 1) both components of alloy distribute to its high theoretical capacity of 824 mAhg-1; 2) alloying/dealloying of Sn and Sb occur at different potentials, which smoothens the mechanical stress.
SnSb + xLi+ + xe- ↔ LixSnSb (0≤x≤1.6)
Li1.6SnSb + 1.4Li+ + 1.4e- ↔ Li3Sb + Sn
Sn + 4.4Li+ + 4.4e- ↔ Li4.4Sn
In the present work, nanoporous SnSb alloy with 3-D pore system and well-developed crystalline framework was successfully obtained via nano-casting method by using a 3-D porous silica as a hard-template. The nanoporous SnSb exhibits high specific surface area of 115 m2g-1, large pore volume of 0.5 cm3g-1 and dual nanopore sizes of 4 and 22 nm. Thus, 3-D nanoporous SnSb showed outstanding rate capabilities up to 2 C as well as high reversible lithium storage capacity of 810 mAhg-1 with excellent coulombic efficiency of 99.3 %.