Fabrication of Advanced Hierarchical Porous Polymer Nanosheets and Their Application in Lithium–Sulfur Batteries

Abstract

Porous polymers have attracted tremendous interest in lithium–sulfur batteries due to the combination of good physical confinement and chemical immobilization to suppress the polysulfide shuttle. Currently, the development of facile and effective methods for fabrication of porous polymers with hierarchical porous structures, strong polar species, and efficient charge-transfer pathways is significant yet challenging, which is crucial for high-performance sulfur cathodes. Herein, for the first time, we present the successful development of a novel class of advanced hierarchical porous polymer nanosheets (AHPPNs) based on a union of surface-initiated atom transfer radical polymerization and a cross-linking-induced coassembly strategy. Due to their well-defined nanoarchitectures, AHPPNs are capable of providing a commendable shuttle-suppressing shield for polysulfides via strong chemisorption, hierarchical porous structures for immobilizing sulfur and relieving volume change, and shortened pathways for ions and electrons. Benefiting from these synergistic effects, the lithium–sulfur batteries assembled with S@AHPPNs cathodes exhibit greatly enhanced rate performance and long stable cycle capability.

Fabrication and Porous Architecture of Crosslinked Polyimides for Lithium–Sulfur Batteries and Their Electrochemical Properties

“…The consequence is due to the welldesired porous channel and the high-content polar N substance of CR-PPI-PE. 43,71 The discharging curve shows two plateau capacities, including the solid−liquid phase conversion of LiPSs (Q SL ) and the following liquid−solid phase transformation (Q LS ). Because of the superior microporous structure and sufficient chemical anchoring sites, 44 S/CR-PPI-PE exhibits superior Q LS (752 mA h g −1 at 0.1 C from the rate test) and retains high capacity retention (68.6% at 0.2 C), as well as maintains considerable capacity (291 mA h g −1 at 1 C) (Figure 7b).…”

“…S/CR-PPI-PE exhibits a better discharge capacity of 298 mA h g –1 after 500 cycles at 1 C with a 0.077% attenuation rate, but S/CR-PPI-BPE possesses an inferior capacity of 272 mA h g –1 . The consequence is due to the well-desired porous channel and the high-content polar N substance of CR-PPI-PE. , …”

“…Many achievements of cathode-based materials have been explored, including metal-based complexes, graphene-based composites, carbon-based substances, and porous polymer-based frameworks. ,,− As we all know, the well-designed porous structure can exhibit superiority in the adsorption capacity and physical confinement of polysulfides, − in which macropores and mesopores offer the accommodation space for LiPSs and micropores alleviate the flow loss of polysulfides. , Thus, the fabrication of cathode materials with fine porosity parameters plays a vital role in improving the electrochemical performance of Li–S batteries. , Recently, porous organic polymers (POPs) have shown great potential for application in lithium–sulfur batteries.…”

Carbon-Based Conductive Frameworks and Metal Catalytic Sites Derived from Cross-Linked Porous Porphyrin-Based Polyimides for Enhanced Conversion of Lithium Polysulfides in Li–S Batteries

“…An important concern involving the scientific problem in Li−S batteries is the shuttle behaviors caused by the dissolution of lithium polysulfides (LiPSs). 29 One of the most effective ways to solve the above problem is to design a reasonable host for the cathode, requiring three conditions: (1) prominent porosity parameters that accommodate vast sulfur, adsorb LiPSs, and carry out physical confinement, (2) efficient electrical frameworks that accelerate charge/ion migration, and (3) intrinsic catalytic effects that promote the oxidation− reduction reaction kinetics. The combination of the above factors realizes the kinetic equilibrium of adsorption− dispersion−conversion to significantly restrain the shuttling behavior of LiPSs.…”

“…Commercially available lithium ion batteries (LIBs) are now suffering from serious technical bottlenecks in reaching the increasing energy standard on account of the restricted theoretical energy density. − Lithium–sulfur batteries (LSBs) are a prospective candidate for next-generation energy devices thanks to their high theoretical specific capacity, gravimetric energy density, abundant sulfur source storage, and convenient sulfur utilization. − Nevertheless, Li–S batteries present technological obstacles, including low sulfur efficiency, poor long-term cycling retention, frustrating self-discharging, and worrisome security hazards, which impede their further large-scale application. − Many researchers focus on the rationalization of material design and optimization of structure configuration to demonstrate the interpretation of improvement strategies and development processes, in which predesigned sulfur cathode, decorated separator, , improved electrolyte, optimized binder, and protective Li anode , are developed to respond to the above challenges. An important concern involving the scientific problem in Li–S batteries is the shuttle behaviors caused by the dissolution of lithium polysulfides (LiPSs) . One of the most effective ways to solve the above problem is to design a reasonable host for the cathode, requiring three conditions: (1) prominent porosity parameters that accommodate vast sulfur, adsorb LiPSs, and carry out physical confinement, (2) efficient electrical frameworks that accelerate charge/ion migration, and (3) intrinsic catalytic effects that promote the oxidation–reduction reaction kinetics.…”