context: Current batteries (especially lithium batteries) have been suffering from a bottleneck in safety issues. For example, these batteries are prone to arouse fires or explosions at extreme temperatures or under external forces, giving rise to significant risks in people's daily lives. Fortunately, the quasi-solid-state COG@MnO2//COG@Zn battery developed in this study exhibits fascinating performance in terms of safety. Firstly, we examined its charge–discharge performance at 60 mA cm−3 in a wide temperature range, and the results are shown in Fig. 4d. At room temperature (25 °C), the battery displays a capacity of 10.3 mA h cm−3. When the temperature is decreased to −20 °C, the capacity of the battery decreases to 6.9 mA h cm−3. Moreover, when the temperature is raised up to 100 °C, the battery can still work normally with a capacity of 13.5 mA h cm−3. Overall, the capacity of the battery increases gradually and reaches the peak at 80 °C as the temperature increases from −20 to 100 °C (Fig. 4e). These results indicate that the ion transport through the gel electrolyte is influenced remarkably by the temperature, and the battery can be safely operated in a wide temperature range. Moreover, to evaluate its safety under a variety of extreme conditions, a series of destructive tests were performed on the quasi-solid-state battery. Surprisingly, the battery is still able to power an electronic temperature humidity meter normally even after being damaged under a variety of extreme conditions, such as puncturing, bending, hammering, cutting and cropping (Fig. 4f and Movies S1–S6†), suggesting its superb safety in daily use.