Hollow heterostructure design enables self-cleaning surface for enhanced polysulfides conversion in advanced...

Constructing interpenetrating heterointerface with reasonable interface energy barriers to improve electron/ion transport and accelerate the deposition/decomposition of lithium sulfide (Li₂S) is an effective method to improve the electrochemical performance of lithium-sulfur (Li-S) batteries. Herein, NiCoO₂/NiCoP heterostructures with hollow nanocage morphology are prepared for efficient multifunctional Li-S batteries. The hollow nanocage structure exposes abundant active sites, traps lithium polysulfides and inhibits the shuttle effect. The NiCoO₂/NiCoP heterostructure, combing strong adsorption capacity of NiCoO₂ and excellent catalytic ability of NiCoP, facilitates the process of anchoring-diffusion-transformation of polysulfides. The successful construction of heterostructures reduces the reaction barrier, accelerating the lithium ion (Li⁺) diffusion rate and thus effectively enhancing the redox reaction kinetics. More importantly, NiCoO₂/NiCoP heterostructure plays a role in self-cleaning that minimizes solid sulfur species accumulation to maintain surface clean during long cycling for a continuously catalysis of the polysulfides conversion reactions. With the merit of these features, the NiCoO₂/NiCoP modified separator exhibits excellent cycling stability with a low capacity decay of 0.043% per cycle up to 1000 cycles at 2 C. The design of NiCoO₂/NiCoP hollow nanocage heterostructures offers a new option for high-performance electrochemical energy storage devices.