Search

Stretchable lithium-ion batteries (LIBs) have attracted great attention as a promising power source in the emerging field of wearable electronics. Despite the recent advances in stretchable electrodes, separators, and sealing materials, building stretchable full batteries remains a big challenge. Herein, a simple strategy to prepare stretchable electrodes and separators at the full battery scale is reported. Then, electrostatic spraying is used to make the anode and cathode on an elastic current collector. Finally, a polyvinylidene fluoride/thermoplastic polyurethane nanofiber separator is hot-sandwiched between the cathode and anode. The fabricated battery shows stable electrochemical performance during repeatable release-stretch cycles. In particular, a stable capacity of 6 mA•h/cm2at the current rate of 0.5 C can be achieved for the fully stretchable LIB. More importantly, over 70% of the initial capacity can be maintained after 100 cycles with ∼150% stretch.

Strain usually exists in two-dimensional (2D) materials and devices, and its presence drastically modulates their properties. When 2D materials interface with noble metals, local strain and surface plasmon can couple at the metal–2D material boundaries, delivering a lot of intriguing phenomena. Current studies are mostly focused on the explanations of these strain-related phenomena based on a static point of view. Although strain can typically be relaxed in many environments, the time evolution of strain at metal–2D material interfaces remains largely unknown. In this work, we investigate the evolution of local strain at Ag–MoS2boundaries by surface-enhanced Raman scattering. With the split of MoS2Raman peaks as an indicator of local strain, it is found that the originally localized strain at Ag–MoS2boundaries evolves and relaxes with time into a delocalized strain in MoS2plane. The time to start the strain relaxation depends on the number of layers of MoS2flakes, suggesting that the relaxation may result from the mechanical instability of the interface between the topmost MoS2layer and the underlying materials. The relaxation occurs in a certain period of time, i.e., ∼70 days for 1L and ∼30 days for 3L. Accompanying the strain relaxation, surface sulfurization of Ag also occurs, a process that reduces the strength of locally enhanced electric field. Our results not only provide a deep understanding of strain evolution at metal–MoS2interfaces but also shed light on the optimization of MoS2-based device fabrications.

The electronic metal-support interaction (EMSI) of heterogenous catalysts has attracted much attention for its enhancing electrocatalytic efficiency by impacting adsorption and desorption energy of reaction intermediates. Herein, we synthesize the monodispersed single-crystal Pt nanoparticles (~3 nm) decorated on MoS2nanosheets with 2 H phase (Pt-MoS2) by a universal wet chemical method. The morphology and structure characterizations show that the loaded Pt single-crystals are approximately half truncated octahedral shapes enclosed by {1 1 1} and {2 0 0} facets. Benefitting from interfacial electronic structure modulation, the Pt-MoS2exhibits a lower overpotential (67.4 mV at the current desity of 10 mA·cm−2), smaller Tafel slope (76.2 mV·dec−1), and robuster HER durability than those of pristine MoS2nanosheets and prepared Pt NPs. The theoretical simulations further reveal that the Pt atom at the interface, which belong to {2 0 0} facets and adjoin S atoms, own the smallest hydrogen adsorption free energy by manipulating the d-band center of the Pt metal surface. This work provides crystalline structure and electronic configuration engineering strategy towards to design and develop of metal-support heterostructure with high HER activity and stability.