Highly Reversible Li-Se Batteries with Ultra-Lightweight N,S-Codoped Graphene Blocking Layer.

ABSTRACT: The desire for practical utilization of rechargeable lithium batteries with high energy density has motivated attempts to develop new electrode materials and battery systems. Here, without additional binders we present 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.

SUBMITTER: Gu X 

PROVIDER: S-EPMC6199105 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature