To overcome the lithium storage barriers of current lithium-ion batteries, it is imperative that conventional low capacity graphite anodes be replaced with other higher capacity anode materials. Silicon is a promising alternative anode material due to its huge energy densities; however, its lithiumconcentration-dependent volumetric changes can induce severely adverse effects that lead to drastic degradations in capacity during cycling. The dealloying of Si-metal alloys is recently suggested as a scalable approach to fabricate high-performance porous Si anode materials. Herein, a microstructure controlled porous Si is developed by the dealloying in conjunction with wet alkaline chemical etching. The resulting 3D networked structure enables enhancement in lithium storage properties when the Si-based material is applied not only as a single active material but also in a graphite-blended electrode.

Real time dilation behaviors of a Si-Ti-Fe-Al alloy electrode adopting a poly (amide-imide) binder were investigated to understand the effects of thermal treatment temperature for PAI binder on the electrochemical performance of the Si-alloy electrode using an in-situ electrochemical dilatometer. In situ measurement of the electrode thickness showed that the changes in the volume of the Si electrode was suppressed by heat treatment greater than 300 C, which well agreed with the improved cycle performance of the Sialloy electrode thermally treated at the same temperature. Differential dilation plots of the Si-alloy electrodes were found to reveal more detailed changes in the volume of the Si-alloy electrode, thus showing that the enhanced mechanical strength of thermally treated PAI effectively could control the expansion and contraction of the Si-alloy electrode and ensuring a more stable cycle performance of the Si-alloy electrode.

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The vanadium redox flow battery (VRFB) is one of the most promising electrochemical energy storage systems for grid support. However, the electrochemical performance of the VRFB should be further improved for successful penetration into the large‐scale energy storage system market. Among all the components of the VRFB, the electrode, which provides an active site for the vanadium ion redox reaction, plays an important role in determining the electrochemical properties of the VRFB. In this work, nitrogen‐doped graphite felts prepared via a direct nitridation route using NH3 were investigated as electrode materials for the VRFB. The resulting N‐doped graphite felt electrode showed much improved voltage efficiency and energy efficiency of 87.1 and 85.0%, respectively, compared to those of pristine graphite felt (82.13 and 79.6%, respectively). These improvements can be attributed to doped nitrogen atoms in the graphite felt electrode acting as an efficient electrocatalyst for the vanadium redox reaction in a VRFB system.