Secondary rechargeable magnesium batteries (RMBs) are lower cost, safer, and have high energy density, making them a potential replacement for lithium-ion batteries. Researchers have prepared CoSe porous polyhedral (CoSe/Te) materials encapsulated by Te. The rich porous structure of this material helps to shorten the Mg2+ diffusion path, which in turn promotes the magnesium storage reaction kinetics of magnesium ion batteries. In addition, the entry of Te elements significantly reduces the difficulty of the reaction, improves the kinetics and redox reversibility, and stimulates the electron conduction, resulting in enhancing the electrochemical properties of batteries. This work provides research ideas for the future development of RMBs.