Conductive Al-Doped ZnO Framework Embedded with Catalytic Nanocages as a Multistage-Porous Sulfur Host in Lithium–Sulfur Batteries
Chenxu Wen, Xiaohang Du, Feichao Wu, Lanlan Wu, Jingde Li, Guihua Liu
Abstract
Lithium–sulfur (Li–S) batteries possess many practical challenges including the lithium polysulfide (LiPS) “shuttle effect” and their sluggish conversion kinetics. To address these issues, a unique hierarchical porous architecture, combining highly conductive ordered macroporous skeleton and embedded microporous particles is rationally designed as a dual-effective polysulfide immobilizer and conversion promoter. In this nanoporous architecture, Al-doped ZnO (AZO) acts as a conductive macroporous framework, profiting chemical anchoring of LiPS as well as facilitating electrolyte infiltration and ion diffusion; Co nanoparticle-anchored N-doped carbon (Co-NC) derived from CoZn-metal–organic framework is embedded in the macropores to further strengthen the LiPS adsorption, catalytically accelerating conversion kinetics of LiPS simultaneously. Consequently, the Co-NC@AZO/S cathode delivers a notable rate capability of 635.5 mA h g–1 at 5 C. A high area capacity of about 5.8 mA h cm–2 with a mass loading of 6.8 mg cm–2 is also achieved under a lean electrolyte (E/S = 5.7). Additionally, the Li–S pouch cells equipped with Co-NC@AZO can be extended to sulfur loading as high as 4.0 mg cm–2, delivering a superb capability of 897.5 mA h g–1 after 100 cycles. This work puts forward a design for stably cycled and practically viable Li–S batteries.