In-plane micro-supercapacitors (MSCs) possess the capabilities of easy integration with planar circuit and feasible flexibility when they are used in flexible and wearable electronics. However, the unsatisfied energy density limits...

Manganese oxide as the star cathode material of aqueous zinc ion batteries is vigorously developed because of its environmental protection, outstanding theoretical capacity, and high voltage. However, severe Jahn–Teller distortion of trivalent Mn has detrimental effect on cyclic stability. Herein, 1D core‐shell bimetal oxide with cross‐doping of heteroatom is successfully designed by self‐template method via one‐step hydrothermal reaction. Specifically, the thick shell of Mo‐doped α‐MnO2 with increased nanopores, expanded lattice spacing, and high oxidation state not only contributes high capacity but also suppresses the lattice distortion due to the doping of high‐valent Mo6+; While the thin core of Mn‐doped MoO3 nanobelt supplies a shaped template, important Mo source, and improved conductive path. Therefore, this composite exhibits a superior capacity of 366.2 mAh g−1 at 0.2 A g−1 and 100% capacity retention after 100 cycles, which effectively increases to 4.1 times from 1.5 times of pure α‐MnO2 based battery. Besides promoting the electrochemical performance in coin‐cell batteries, composite materials also balance the electrochemical and mechanical performances in flexible micro‐batteries with area energy density of 261.2 µWh cm−2. Therefore, this synergetic self‐template and cross‐doping strategy can extend to the material design of other high‐performance metal oxides for energy storage application.

The interface adhesion plays a key role between rigid metal and elastomer in compressible and stretchable conductors. However, the poor interfacial adhesion hinders their wide applications. To strengthen the interface adhesion, herein, a combination strategy of structure interlocking and polymer bridging is designed by introducing a method of subsurface‐initiated atom transfer radical polymerization (sSI‐ATRP). This method can make polymer brush root in polydimethylsiloxane (PDMS) subsurface, on this basis, metals further grow from subsurface to surface of PDMS via electroless deposition. As a result, the adhesive strength (≈2.5 MPa) between metal layer and PDMS elastomer is 4 times higher than that made by common polymer modification. As a demonstration, pressure sensor is constructed by using as‐prepared compressible 3D Cu sponge as a top electrode and paper‐based interdigited metal electrode as a bottom electrode. The device sensitivity can reach up to 961.2 kPa−1 and the durability can arrive at 3 000 cycles without degradation. Thus, this proposed interface‐enhancement strategy for rigid‐soft materials can significantly promote the performance of piezoresistive pressure sensors based on 3D conductive sponge. In the future, it would also be expanded to the fabrication of stretchable conductors and extensively applied in other flexible and wearable electronics.