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Application of Si anodes is hindered by severe capacity fading due to pulverization of Si particles during the large volume changes of Si during charge/discharge and repeated formation of the solid‐electrolyte interphase. To address these issues, considerable efforts have been devoted to the development of Si composites with conductive carbons (Si/C composites). However, Si/C composites with high C content inevitably show low volumetric capacity because of low electrode density. For practical applications, the volumetric capacity of a Si/C composite electrode is more important than gravimetric capacity, but volumetric capacity in pressed electrodes is rarely reported. Herein, a novel synthesis strategy is demonstrate for a compact Si nanoparticle/graphene microspherical assembly with interfacial stability and mechanical strength achieved by consecutively formed chemical bonds using 3‐aminopropyltriethoxysilane and sucrose. The unpressed electrode (density: 0.71 g cm−3) shows a reversible specific capacity of 1470 mAh g−1 with a high initial coulombic efficiency of 83.7% at a current density of 1 C‐rate. The corresponding pressed electrode (density: 1.32 g cm−3) exhibits high reversible volumetric capacity of 1405 mAh cm−3 and gravimetric capacity of 1520 mAh g−1 with a high initial coulombic efficiency of 80.4% and excellent cycling stability of 83% over 100 cycles at 1 C‐rate.

Herein, we report the in‐situ synthesis of amorphous GeSe/CNT composite via defective‐carbon‐mediated chemical bonding for ultrastable Na‐ion storage. Structural defects in CNTs play a crucial role in the chemical bonding and bonding strength in GeSe/CNTs composites. Specifically, the bonding strength tends to increase with increasing defect concentrations of CNTs. Remarkably, the strong chemical bonding between GeSe and CNTs significantly weakens Ge−Se bonds and promotes amorphization of GeSe, thus facilitating a reversible conversion reaction and enhancing Na‐ion diffusion. Consequently, GeSe/CNTs composite exhibits outstanding cyclability of 87.9% even after 1000 cycles at 1 A g−1 and a high‐rate capability of 288.3 mA h g−1 at 10 A g−1. Our work presents a promising approach for the amorphization of electrode materials enabled by the defective‐carbon‐mediated strong chemical bonding for Li‐, Na‐, and K‐ion batteries.