Two-dimensional transition metal oxyhydroxide (MOOH) nanostructures show great potential for application in catalysis, sensing, secondary batteries, and supercapacitors fields. Nonetheless, it is still a challenge to orient and hybridize MOOH nanosheets with carbon-free conductive materials (e.g., CuSe), and their uses in flexible inplane asymmetric microsupercapacitors (AMSCs) are not explored. Herein, vertically oriented CuSe@FeOOH and CuSe@MnOOH hybrid nanosheet frameworks are alternately integrated on Au interdigital electrodes/polyethylene terephthalate substrate through a successive electrodeposition strategy without any template. Because of the unique geometric motifs and composition combination, those hybrid nanosheets frameworks exhibit greatly enhanced specific capacitance (543.9 F g −1 for CuSe@ FeOOH, 422.9 F g −1 for CuSe@MnOOH). An in-plane AMSCs (CuSe@FeOOH// CuSe@MnOOH) is directly assembled by using poly(vinyl alcohol)-LiCl gel as the electrolyte. The as-fabricated AMSCs manifests large areal capacitance (20.47 mF cm −2 ), remarkable cycle stability (95% remained after 32 000 cycles), excellent flexibility and mechanical stability. Moreover, it also exhibits a high volumetric energy density of 16.0 mW h cm −3 and a power density of 1299.4 mW cm −3 , outperforming most recently reported in-plane microsupercapacitors. This work may promote the development of MOOH-based two-dimensional heteronanostructures and accelerate their applications in flexible energy storage or other clean energy fields.

Pd‐based nanoalloys are promising electrocatalysts for replacing Pt‐based ones toward oxygen reduction reaction. Despite that great progress has been achieved, universally synthesizing Pd‐based alloy nanosheets and further integrating them into porous or hierarchical superstructures remain a challenge, and their ORR performances are not systematically investigated. Herein, novel ultrathin and highly wrinkled Pd−M (M=Cr, Mo, W) alloy nanosheets flower‐like superstructures (NSFSs) are universally fabricated via a polyether and small molecules/ions ligand assisted solvothermal method. Such Pd−M NSFSs possess mesoporous structures and co‐exist single‐atom‐like and cluster‐like M species on their surfaces. Compared with pure Pd NSFSs, those Pd−M NSFSs show greatly enhanced ORR activity in alkaline media. Due to the unique microstructure feature, proper alloy constituent and stronger interatomic polarization or electronic coupling, the Pd−W NSFSs show the highest ORR activity with the half‐wave potential of 0.89 V (vs. RHE) and mass activity of 0.46 A mgPd−1 at 0.90 V (vs. RHE), outperforming commercial Pt/C, and most of reported Pd(or Pt)‐based catalysts. Moreover, the Pd−W NSFSs manifest outstanding durability and anti‐CO poisoning ability yet. This work may spur the development of 2D Pd‐based nanoalloy superstructures and promote their applications in fuel cells or other clean energy fields.

Quo, Qus and η were derived from a photocurrent–time curve to quantitatively characterize the charge storage of a ZnO-based nanorod array film.