The desire for practical utilization of recharge-able lithium batteries with high energy density has moti-vated attempts to develop new electrode materials and battery systems. Here, without additional binders we pre-sent a simple vacuum filtration method to synthesize nitrogen and sulfur codoped graphene (N,S-G) blocking layer, which is ultra-lightweight, conductive, and free standing. When the N,S-G membrane was inserted between the catholyte and separator, the lithium–selenium (Li–Se) batteries exhibited a high reversible discharge capacity of 330.7 mAh g-1 at 1 C (1 C=675 mA g-1) after 500 cycles and high rate performance (over 310 mAh g-1 at 4 C) even at an active material loading as high as～5 mg cm-2. This excellent performance can be ascribed to homogenous dispersion of the liquid active material in the electrode, good Li+-ion conductivity, fast electronic transport in the conductive graphene framework, and strong chemical confinement of polyselenides by nitrogen and sulfur atoms. More importantly, it is a promising strategy for enhancing the energy density of Li–Se batteries by using the catholyte with a lightweight heteroatom doping carbon matrix.