Solid-state Li batteries using Na + superionic conductor type solid electrolyte attracts wide interest because of its safety and high theoretical energy density. The NASCION type solid electrolyte LAGP (Li 1. 5 Al 0.5 Ge 0.5 P 3 O 12 ) shows favorable conductivity as well as good mechanical strength to prevent Li dendrite penetration. However, the instability of LAGP with Li metal remains a great challenge. In this work, an amorphous Ge thin film is sputtered on an LAGP surface, which can not only suppress the reduction reaction of Ge 4+ and Li, but also produces intimate contact between the Li metal and the LAGP solid electrolyte. The symmetric cell with the Ge-coated LAGP solid electrolyte shows superior stability and cycle performance for 100 cycles at 0.1 mA cm −2 . A quasi-solid-state Li–air battery has also been assembled to further demonstrate this advantage. A stable cycling performance of 30 cycles in ambient air can be obtained. This work helps to achieve a stable and ionic conducting interface in solid-state Li batteries.
Liu Lili,Wang Xiaoyang,Zhang Xiaohong,Zhang Xiuyun,Chen Shimou
Germanium-based materials as anode can improve the capacity of lithium-ion battery because of its excellent lithium-ion storage ability. But the application of Ge anode is hampered by the huge volume variation during de/lithiation processes. Herein, a Ge/Cu wire mesh (Ge/Cu-WM) electrode is prepared by ionic liquid electrodeposition, where the Ge nano-film is deposited on Cu wire mesh. The unique structure of Ge/Cu-WM electrode not only buffers the volume expansion but also enhances electron migration and electron transport during lithiation. The Cu 3 Ge is observed by XRD, which confirms that the Ge nano-film tightly attach to the Cu wires. All structural properties give the electrode excellent electrochemical performance, where a capacity of 633 mAh/g after 100 cycles at 0.1 C is obtained. The reasonable structure and improved cycling stability make Ge-based anodes highly attractive for lithium-ion battery applications.