Rechargeable magnesium-ion (Mg-ion) batteries have attracted wide attention for energy storage. However, magnesium anode is still limited by the irreversible Mg plating/stripping procedure. Herein, a well-designed binary Bi₂O₃-Bi₂S₃ (BO-BS) heterostructure is fulfilled by virtue of the cooperative interface and energy band engineering targeted fast Mg-ion storage. The built-in electronic field resulting from the asymmetrical electron distribution at the interface of electron-rich S center at Bi₂S₃ side and electron-poor O center at Bi₂O₃ side effectively accelerates the electrochemical reaction kinetics in the Mg-ion battery system. Moreover, the as-designed heterogenous interface also benefits to maintaining the electrode integrity. With these advantages, the BO-BS electrode displays a remarkable capacity of 150.36 mAh g⁻¹ at 0.67 A g^–1 and a superior cycling stability. This investigation would offer novel insights into the rational design of functional heterogenous electrode materials targeted the fast reaction kinetics for energy storage systems.

Rationally designing sulfur hosts with the functions of confining lithium polysulfides (LiPSs) and promoting sulfur reaction kinetics is critically important to the real implementation of lithium-sulfur (Li-S) batteries. Herein, the defect-rich carbon black (CB) as sulfur host was successfully constructed through a rationally regulated defect engineering. Thus-obtained defect-rich CB can act as an active electrocatalyst to enable the sulfur redox reaction kinetics, which could be regarded as effective inhibitor to alleviate the LiPS shuttle. As expected, the cathode consisting of sulfur and defect-rich CB presents a high rate capacity of 783.8 mA·h·g^-1 at 4 C and a low capacity decay of only 0.07% per cycle at 2 C over 500 cycles, showing favorable electrochemical performances. The strategy in this investigation paves a promising way to the design of active electrocatalysts for realizing commercially viable Li-S batteries.