Journal Article

Synthesis and Electrochemical Characterization of Nickel Germanate as an Electrode Material for Lithium‐Ion Batteries

Krasilina, Darina A., Khrapova, Ekaterina K., Grushina, Anna A., Rumyantsev, Aleksandr M., Krasilin, Andrei A., Zharova, Ekaterina D.

2026

Overview

Here, we report on a study of nickel germanate formation in the Ni(OH)2–GeO2 system under solid‐phase synthesis conditions in the 500–800°C temperature range and on the research of electrochemical performance of Ni2GeO4‐based electrodes. It is shown that the Ni2GeO4 formation occurred at temperatures around 700°C, and the process began with the melting of the nonautonomous phase GeO2 at Tm2n = 725 ± 112°C. The nickel germanate‐based electrodes showed a rapid decrease in capacity over 40 cycles. However, starting from the 80th cycle, a gradual increase in capacity was observed from 190 to 528 mAh/g at the 270th cycle. We attribute this increase in capacity to evolution in the specific surface area and porosity of the electrode material during long‐term cycling. Formation of Ni2GeO4 during solid‐phase reaction is studied in the 500–800°C range. Intense Ni2GeO4 growth occurs around 700°C, and it is related to GeO2 melting. The Ni2GeO4‐based electrodes show a rapid decrease in capacity over 40 cycles. Starting from the 80th cycle, an increase in capacity is observed from 190 to 528 mAh/g at the 270th cycle.

• Subject: electrodes of lithium‐ion batteries / germanium oxide / nickel germanate / nickel oxide / nonautonomous phase