A concentration-gradient composition is proposed as an effective approach to solve the mechanical degradation and improve the electrochemical cyclability for cathodes of sodiumion batteries. Concentration-gradient shell NaxNiyMn1-yFe(CN)6• nH2O, in which the Ni content gradually increases from the interior to the particle surface, is synthesized by a facile co-2 precipitation process. The as-obtained cathode exhibits an improved electrochemical performance compared to homogeneous NaxMnFe(CN)6• nH2O, delivering a high reversible specific capacity of 110 mA h g-1 at 0.2 C and outstanding cycling stability (93% retention after 1000 cycles at 5 C). The improvement of electrochemical performance can be attributed to its robust microstructure that effectively alleviates the electrochemically induced stresses and accumulated damage during sodiation/desodiation and thus prevents the initiation of fracture in the particles upon long term cycling. These findings render a prospective strategy to develop high-performance electrode materials for sodium-ion batteries. TOC GRAPHICS Sodium ion batteries (SIBs) have been gaining increased attention as a potential energy storage device. 1-4 Compared to lithium, sodium is available abundantly and relatively inexpensive, thereby reducing the cost of the electrode material. Moreover, sodium has similar electrochemical properties to lithium and maintains a good reversibility in a variety of host materials. Hence,

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Atomic force microscopy indentation was employed to illustrate that pentoxifylline reduces the elastic modulus of red blood cells (from healthy human subjects), increasing hence their flexibility.

A promising materials engineering method for improving the strength of crystalline materials is to add obstacles to dislocation motion that induce interface hardening (IH) or precipitate hardening (PH). In this study, molecular dynamics simulations are performed for Ni/graphene composites, revealing for the first time that graphene can strengthen the Ni matrix not only strictly via IH or PH but also through a continuous transition between the two. When graphene behaves like an interface, dislocation pileups form, whereas when it behaves as a precipitate, complex Orowan looping occurs by dislocation cross-slip. IH transitions to PH when the integrity of the graphene-dislocation configuration (GDC) deteriorates, leading to a reduced strengthening effect. Furthermore, the deformation of graphene is found to be an effective signature to indicate the real-time strengthening. This observation relates the graphene strengthening effect on metals to a combination of parameters, such as the GDC integrity, graphene deformation, and dislocation evolution, opening an avenue to tune the mechanical properties by controlling the dislocation movements and manipulating the dislocation–obstacle interaction mechanisms.