context: To investigate the electrochemical reaction mechanism of Zn2+ in the NV NSs@ACC//Zn battery, ex situ XRD and XPS analyses are carried out. Fig. 5a shows the different charge/discharge states during the 2nd cycle at 0.1 A g−1. During the discharge process, it can be observed that a small amount of (NH4)2V10O25·8H2O transforms to the new phase of Zn3(OH)2V2O7·2H2O (JCPDS no. 50-0570) (Fig. 5b), which could be attributed to H+/Zn2+-co-insertion into the VO layers. The peaks between the range of 10–35° for the samples cha.0.8 V and cha.1.4 V were more obvious than that for the discharge process. This is attributed to the XRD pattern of Zn(OH)2 impurity, which could arise from the deposited Zn(OH)2@glass fiber adhered on the surface of the sample. In addition, as can be seen in Fig. 5c, the peak for the (001) plane evidently shifts to a lower degree from 8.3 to 6.7° after immersion in the electrolyte for 1 h, corresponding to an increase in the interlayer spacing from 10.6 Å to 13.2 Å. Note that the interlayer distance during the subsequent discharge/charge process is always larger than that of the pristine sample, revealing that the expansion of the layer spacing upon immersion arose from water molecule intercalation, which can weaken the electrostatic attraction and thus facilitate the migration of multivalent Zn2+. More significantly, the diffraction peak (001) of NV NSs@ACC shifts to a lower degree during the discharge process and almost moves back to its original position during the charge process. The d-spacing of the (001) plane in different samples corresponding to the ex situ XRD patterns are presented in Table S4.† These results indicate the highly reversible Zn2+ intercalation/deintercalation of the NV host without the destruction of its open-framework during the subsequent discharge/charge process.