Intimately coupled carbon/molybdenum‐based hierarchical nanostructures are promising anodes for high‐performance sodium‐ion batteries owing to the combined effects of the two components and their robust structural stability. Mo–polydopamine (PDA) complexes are appealing precursors for the preparation of various Mo‐based nanostructures containing N‐doped carbon (NC). A facile method for the fabrication of hierarchical tubular nanocomposites with intimately coupled MoSe2 and NC nanosheets has been developed, which involves the preparation of Mo–PDA hybrid nanotubes through a chemical route followed by two heat treatments. The strong coupling between Mo anions and the catechol groups in dopamine not only restricts the crystallite size but also inhibits agglomeration during selenization, resulting in few‐layered MoSe2 nanosheets embedded in hierarchical NC substrates. The as‐synthesized nanotube composites are constructed by assembling primary MoSe2/NC nanosheets. This unique structure not only increases the number of active sites but also shortens the diffusion length of ions and enhances the electronic conductivity of electrode materials. The as‐synthesized hierarchical MoSe2/NC nanotubes deliver a high capacity of 429 mAh g−1 at 1 A g−1 after the 150th cycle when used as anodes in sodium‐ion batteries. Furthermore, at a high current density of 10 A g−1, a high discharge capacity of 236 mAh g−1 is achieved.

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The inner ear hair cells, the receptors sensing mechanical stimuli such as acoustic vibration and acceleration, achieve remarkably high sensitivity to miniscule stimuli by selectively amplifying small inputs. The gating springs hypothesis proposes that a phenomenon called negative stiffness is responsible for the nonlinear sensitivity. According to the hypothesis, the bundle becomes more sensitive in certain region as its stiffness changes due to the opening or closing of transduction channels, which in turn exert force in the same direction of the bundle’s displacement. In this study, we developed a conceptual model of an inertial sensor inspired by the inner ear hair cells, focusing on the hair cell’s amplifying mechanism known as negative stiffness. The negative stiffness was applied to a simple mass-spring-damper system with nonlinear spring derived from gating springs hypothesis. Sinusoidal stimuli of 0.1Hz~10Hz with magnitude of 1pN to 1000pN were applied to the system to match the dynamic range of vestibular organs. Simulation on this nonlinear model was performed on MATLAB, and power transfers and sensitivities in both transient and steady states were obtained and compared with those from the system with linear spring. Parameters were chosen in relation to those of the hair bundle to reproduce operating conditions of both the hair cells and micro inertial sensors. The suggested model displayed compressive nonlinear sensitivity resulting from selective amplification of smaller stimuli despite the energy loss due to large viscous damping typical in micro systems.

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