It remains important to maximize energy density of wearable batteries. In addition, such batteries should be compliant, safe, and environmentally sustainable. Intrinsically safe zinc–manganese dioxide (Zn/MnO2) batteries are great candidates for powering wearables. However, achieving flexibility of these systems is hindered by the absence of a binder that ensures mechanical integrity of the MnO2 electrode composite. Herein, a unique approach to fabricate a mechanically robust MnO2 electrode is presented. Polyvinyl alcohol (PVA)/polyacrylic acid (PAA) gel cross‐linked in situ via thermal treatment is used as a binder for the electrode. Furthermore, energy density and rate capability of the printed battery electrodes are improved by replacing graphite with single‐walled carbon nanotubes (CNTs). The batteries retain 93% capacity when the discharge rate is increased from C/10 to C/3, as well as 97% of their capacity after being flexed. In contrast, batteries based on conventional composition retain 60% and 23% of the capacity, respectively. Finally, the battery with the modified electrode has high areal energy density of 4.8 mWh cm−2 and volumetric energy density of 320 mWh cm−3.