Construction of Ultrathin Layered MXene-TiN Heterostructure Enabling Favorable Catalytic Ability for High-Areal-Capacity Lithium-Sulfur Batteries

Hao Wang; Zhe Cui; Shu-Ang He; Jinqi Zhu; Wei Luo; Qian Liu; Rujia Zou

doi:10.1007/s40820-022-00935-0

Construction of Ultrathin Layered MXene-TiN Heterostructure Enabling Favorable Catalytic Ability for High-Areal-Capacity Lithium-Sulfur Batteries

Nanomicro Lett. 2022 Sep 17;14(1):189. doi: 10.1007/s40820-022-00935-0.

Authors

Hao Wang¹, Zhe Cui¹, Shu-Ang He¹, Jinqi Zhu¹, Wei Luo², Qian Liu³, Rujia Zou⁴

Affiliations

¹ State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, People's Republic of China.
² State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, People's Republic of China. wluo@dhu.edu.cn.
³ Department of Physics, College of Science, Donghua University, Shanghai, 201620, People's Republic of China.
⁴ State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, People's Republic of China. rjzou@dhu.edu.cn.

Abstract

Catalysis has been regarded as an effective strategy to mitigate sluggish reaction kinetics and serious shuttle effect of Li-S batteries. Herein, a spherical structure consists of ultrathin layered Ti₃C₂T_x-TiN heterostructures (MX-TiN) through in-situ nitridation method is reported. Through controllable nitridation, highly conductive TiN layer grew on the surface and close coupled with interior MXene to form unique 2D heterostructures. The ultrathin heterostructure with only several nanometers in thickness enables outstanding ability to shorten electrons diffusion distance during electrochemical reactions and enlarge active surface with abundant adsorptive and catalytic sites. Moreover, the (001) surface of TiN is dominated by metallic Ti-3d states, which ensures fast transmitting electrons from high conductive MX-TiN matrix and thus guarantees efficient catalytic performance. Calculations and experiments demonstrate that polysulfides are strongly immobilized on MX-TiN, meanwhile the bidirectional reaction kinetics are catalytically enhanced by reducing the conversion barrier between liquid LiPSs and solid Li₂S₂/Li₂S. As a result, the S/MX-TiN cathode achieves excellent long-term cyclability with extremely low-capacity fading rate of 0.022% over 1000 cycles and remarkable areal capacity of 8.27 mAh cm^-2 at high sulfur loading and lean electrolytes.

Keywords: Electrochemical catalysis; Li–S batteries; MXenes; Ti3C2Tx-TiN; Ultrathin 2D structures.