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Here, we demonstrate the in situ growth of SnO 2 nanosheets on a freestanding carbonized eggshell membrane (CEM), which provides three-dimensional, bicontinuous electron and ion transport pathways through a massively interconnected carbon fiber skeleton and interpenetrated pore network, respectively. This CEM has other advantages such as the ability to alleviate mechanical stress during cycling as a buffer matrix. When used as an additive-free anode in a sodium-ion battery, SnO 2 nanosheets can realize a complete electrochemical reaction and maintain good cycling stability with the help of a CEM. For instance, SnO 2 nanosheets delivered a high reversible capacity of 656 mA h g -1 in the 5th cycle at 0.1 A g -1 , approaching 98% of its theoretical specific capacity, and maintained a high reversible specific capacity of 420 mA h g -1 after 200 cycles at 0.2 A g -1 .

In this letter, we report a facile self-foaming strategy to synthesize Ni 3 C nanoparticles embedded in a porous carbon network (Ni 3 C@PCN) by rationally incorporating a nickel salt precursor into the carbon source. As a novel hydrogen evolution reaction (HER) catalyst, the Ni 3 C@PCN shows superior catalytic activity with an onset potential of -65 mV, an overpotential of 262 mV to achieve 50 mA cm -2 current density, a Tafel slope of 63.4 mV/dec, and durability over 12 h in acidic media. The excellent performance of the novel 3D composite material along with its low-cost merits is suggestive of great potential for scalable electrocatalytic H 2 production.

Sodium ion batteries (NIBs) have been considered as an alternative for Li ion batteries (LIBs). NaTi2(PO4)3 (denoted as NTP) is a superior anode material for NIBs. However, the poor electrochemical performance of NTP resulting from the low electronic conductivity prevents its application. Here, NTP nanoparticles embedded in carbon network (denoted as NTP/C) were fabricated using a simple soft-template method. This anode material exhibits superior electrochemical performance when used as anode electrodes for NIBs, including highly reversible capacity (108 mAh g(-1) at 100 C) for excellent rate performance and long cycle life (83 mAh g(-1) at 50 C after 6000 cycles). The excellent sodium storage property can be resulted from the synergistic effects of nanosized NTP, thinner carbon shell and the interconnected carbon network, leading to the low charge transfer resistance, the large surface area for electrolyte to soak in and enough void to buffer the volume variation during the repeated cycle.