Few layered graphene wrapped Sn4P3 with high initial coulombic efficiency and cyclic stability for reversible Li+ storage

Abstract

To enhance the rate capability and cyclic stability, we develop few layered graphene wrapped nanocrystalline/amorphous Sn4P3 (named as Sn4P3@FLG) by ball milling. The high energy output of vibrational ball milling enables tight contact of Sn4P3 with FLG via POC bonding as well as compact structure with a high tap density of 4.5 g cm−3. The constraint of FLG not only enhances kinetics of electron and Li+ transfer, but also relieves the volume variation and particle aggregation of Sn4P3 during the lithiation/delithiation process. Therefore, Sn4P3@FLG exhibits superior rate and cyclic performance when evaluated as anode material for lithium-ion batteries. At 0.1 A g−1, it delivers a high reversible capacity of 1077.6 mA h g−1 with a high coulombic efficiency of 89.0% in the first cycle. Even at 1 A g−1, it still retains 929.6 mA h g−1 after 830 cycles. Furthermore, when matched with commercial LiFePO4 cathode in a full cell, it delivers a reversible capacity of 778.0 mA h g−1, with a coulombic efficiency of 79.4%. Considering the high tap density of 4.5 g cm−3, the volumetric capacity of Sn4P3@FLG can be as high as 3500 A h dm−3. Therefore, Sn4P3@FLG can be a promising anode material for high performance lithium-ion batteries.