The accelerated development of miniaturized and customized electronics has stimulated the demand for high-energy microbatteries (MBs) as on-chip power sources for autonomous state operations. However, commercial MBs with thin-film configurations exhibit insufficient energy and power density due to their limited active materials and sluggish ion diffusion kinetics. In order to simultaneously enhance electrochemical performance and maintain low-cost production, efforts have been devoted to constructing three-dimensional battery architectures. This review summarizes the state-of-the-art progress in designing and fabricating microelectrodes for microbattery assembly, including the top-down etching and bottom-up printing techniques, with a particular focus on elucidating the correlations between electrode structures, battery performance, and cost-effectiveness. More importantly, advancements in post-lithium batteries based on sodium, zinc and aluminum are also surveyed to offer alternative options with potentially higher energy densities and/or lower battery manufacturing costs. The applications of advanced MBs in on-chip microsystems and wearable electronics are also highlighted. Finally, conclusions and perspectives for the future development of MBs are proposed.

The switching of quadratic nonlinear optical (NLO) effects between two or more NLO states of solid-state materials represents an intriguing new branch in the field of photoelectrics and optics. While structural phase transitions have shown potential in this field, near-room-temperature reversible NLO switches have rarely been reported. To exploit new NLO switching materials within the structurally flexible class of hybrid perovskites, here, we synthesize a one-dimensional perovskite-like hybrid, (MP)PbBr₃ (where MP⁺ is a 1-methylpyrrolidinium cation), through a facile solution method, which exhibits strong second harmonic generation (SHG) activities with an intensity of ~1.6 times as large as potassium dihydrogen phosphate. Intriguingly, (MP)PbBr₃ enables the near-room-temperature reversible switching of SHG properties, showing a large NLO switching contrast of up to ~40 between its SHG-active and SHG-inactive phases, beyond most of its liquid counterparts. Further microscopic structural analyses reveal that the dynamic ordering of the organic MP⁺ cation and inorganic chain-like skeleton triggers its centrosymmetric (P6₃/mmc) to acentric (P2₁2₁2₁) phase transition at 316 K upon cooling, resulting in a crucial contribution to its NLO switching properties. This work illustrates the potential of this material as a candidate for solid-state NLO switches and will promote the development of NLO materials within the family of low-dimensional hybrid perovskites.

Metal-organic frameworks (MOFs) with tailorable structures and building blocks have demonstrated their advantages in improving the long-term stability of perovskite solar cells (PSCs). However, the inferior conductivity of MOFs and their lack of strong chemical interaction with perovskites cause undesirable interfacial charge carrier recombination and then deteriorate the photovoltaic (PV) performance of PSCs. This perspective offers an insightful overview of the versatile functionalities and key merits of MOFs for stabilizing PSCs under various external stimuli in terms of MOF interlayers and MOF-perovskite heterostructures. To tackle the charge transport problem of MOFs, promising strategies are outlined to improve the intrinsic conductivity and chemical coordination of MOFs, with the aim of achieving long-term stable PSCs without compromising their PV performance. The current challenging issues and potential solutions are also discussed to provide a roadmap for MOF-tailored PSCs towards practical applications.

The effects of cold rolling and subsequent annealing on the microstructures and mechanical properties of Fe₄₀Mn₂₀Cr₂₀Ni₂₀ high-entropy alloys (HEAs) are investigated. The Cr-rich secondary phases with a tetragonal structure (σ phases) in the Fe₄₀Mn₂₀Cr₂₀Ni₂₀ HEAs are precipitated upon annealing at 600 °C-900 °C for 2 h. The prepared Fe₄₀Mn₂₀Cr₂₀Ni₂₀ HEA annealed at 800 °C for 2 h after cold rolling has a good combination of strength and elongation, with a high yield strength of 438 MPa, a high ultimate tensile strength of 676 MPa, and an excellent elongation to fracture of 32%. The mechanical properties at cryogenic temperature are better than those at room temperature. Typically, for the incompletely recrystallized alloy annealed at 700 °C, the yield strength, tensile strength, and elongation after fracture are increased by 26%, 22%, and 100%, respectively. This trend mainly depends on dislocation and twinning strengthening. The σ phases also improve the cryogenic tensile properties. Furthermore, the recrystallization kinetics of the Fe₄₀Mn₂₀Cr₂₀Ni₂₀ HEAs are explored to correlate with the deformation behavior.

Lithium-ion batteries have made significant commercial and academic progress in recent decades. Zinc oxide (ZnO) has been widely studied as a lithium-ion battery anode due to its high theoretical capacity of 987 mAh g^-1, natural abundance, low cost, and environmental friendliness. However, ZnO suffers from poor electronic conductivity and large volume variation during the battery discharge/charge process, leading to capacity deterioration during long-term cycling. Herein, porous ZnO@C nanoplates are developed to offer short ion diffusion pathways and good conduction networks for both Li ions and electrons. The porous nanoplates provide abundant active sites for electrochemical reactions with minimized charge transfer impedance. As a result, the porous ZnO@C nanoplates deliver higher performance for lithium-ion storage compared with a bare ZnO anode. Furthermore, with the introduction of reduced graphene oxide (rGO), the ZnO@C@rGO composite anode achieves a capacity of 229.3 mAh g^-1 at a high current density of 2 A g^-1.