Electrospraying preparation of metal germanate nanospheres for high-performance lithium-ion batteries and room-temperature gas sensors

Metal germanate nanospheres including Ca2Ge7O16, Zn2GeO4 and SrGe4O9 were successfully synthesized by a direct and large-scale electrospraying method. As anodes for lithium ion batteries, the prepared metal germanate nanospheres showed high electrochemical lithium storage performance including excellent cycling stability and high rate capacity. Especially, the Ca2Ge7O16 nanosphere anode delivered a high specific capacity of similar to 670 mA h g(-1) at 0.2 A g(-1). The capacity retention was maintained around 71% even after 500 cycles. Moreover, when applied as room-temperature ammonia gas sensors, all three prepared germinate nanospheres showed significant sensing response values (6.04 for SrGe4O9, 2.73 for Zn2GeO4 and 1.70 for Ca2Ge7O16), fast response-recovery time, excellent stability and outstanding selectivity.