A N/Co co-doped three-dimensional porous carbon as cathode host for advanced lithium–selenium batteries

Selenium (Se) is a promising cathode material for lithium batteries due to its high volumetric energy density (2528 Wh·L⁻¹). However, its practical application is restricted by rapid capacity fading resulting from the shuttle effect and slow reaction kinetics. Herein, a N/Co co-doped three-dimensional porous carbon (Co-NC) is prepared and used as Se host for lithium–selenium batteries (LSeBs). Co-NC displays a high specific surface area of 1201 m²·g⁻¹ which benefits from N and Co doping. The N and Co not only enhance the electrical conductivity of porous carbon but also possess an adsorption effect on polyselenide. Thus, Se/Co-NC electrode exhibits excellent cycling performance (a stable specific capacity of 480 mAh·g⁻¹ after 200 cycles at 1.0C with a much low-capacity decay of 0.028% per cycle) and outstanding rate performance (a high specific capacity of 414 mAh·g⁻¹ at 5.0C). This work inspires highly stable Se cathode design for LSeBs. Graphical abstract: [Figure not available: see fulltext.]