The performance of 3D printed VS2 was subsequently analysed and compared to tape-casted electrodes (Figure ). The 3D printed VS2 electrodes show significantly higher areal capacity (~ 4.98 mAh cm -2 vs ~ 0.48 mAh cm -2 after 10 cycles) as a consequence of the higher loading of VS2 (Figure ). Interestingly, the capacity of the printed cathode rapidly increases during the first ~ 10 cycles, before reaching a stable performance. The increase of capacity during this activation process can be attributed to the transformation of VS2 into electrochemically-oxidised VS2, as reported by Yang et al. In order to prevent the electrochemical conversion of the material during operation, VS2 electrodes were preliminary soaked in the WISE electrolyte for 14 days to promote the controlled growth of an electrochemically-active surface layer of oxide. SEM imaging demonstrates that the morphology of the microflowers is not altered during the conversion process (Figure ). After 14 days of soaking, EDS and XRD evidence the presence of vanadium disulfide, indicating that only the surface layer of the microflowers is converted to amorphous oxide (Figure ). The 3D printed VS2 electrodes achieved an areal capacity of ~1.98 mAh cm -2 after soaking (vs. ~ 0.57 mAh cm -2 for bare 3D printed VS2 electrodes in the first cycle, Figure ), with a stable response even in the first charge-discharge cycles (Figure ). In terms of gravimetric performance, 3D printed VS2 electrodes achieved a stable gravimetric capacity of ~72 mAh g -1 at a current density of 36 mA g -1 (Figure ). Owing to the high conductivity of the printed structures, the electrodes retained a capacity of ~ 0.88 mAh cm -2 when discharge at a high specific current of 7 mA cm -2 (Figure ). Additionally, the soaking treatment ensured a high cycling stability, with a capacity retention higher than 55% after 150 cycles. The application of the 3D printed battery for portable electronics was demonstrated by encapsulating the electrodes inside a 3D printed case and using it to power an LED display (Figure ).