Abstract
Recently, because of the emerging market for portable device and electric vehicles, the development of high energy lithium ion batteries was urgent required. In high energy lithium ion batteries development, the areal capacity is an important indicator. The areal capacity of commercial negative electrode is around 4 m Ah/cm2, that most of the negative material literature were still lower than it. Here we report the novel structure of electrode by using germanium nanowires as lithium-ion battery anode to achieve 2.5 times commercial areal-capacity. Germanium nanowires and copper nanowires were combined to manufacture germanium/copper nanowires fabrics with a layer-by-layer structure. The electrodes fabricated by using several nanowires fabrics and c-PAA-CMC to form a multi-layered structure which contain lot of active material on its unit area. By different layers of the multi-layered structure electrode, the high areal capacity are showing as followed. The 2 layers structure loading 5.3 mg Ge NWs exhibited the reversible areal capacity of ~5 m Ah/cm2 at the charge/discharge current 1.2 mA/cm2 after 50 cycles, and the 3 layers structure loading 8.5 mg Ge NWs performed the reversible areal capacity of ~10 m Ah/cm2 at the charge/discharge current 1.0 mA/cm2 after 20 cycles. Moreover, we successfully assemble the full battery by using a LiNiCoMnO2 cathode, which the areal capacity can achieve to ~6 m Ah/cm2 at the charge/discharge current 1.08 mA/cm2 after 50 cycle and the full battery can provide large capacity for uses on light-emitting-diodes (LEDs) and electric fan.