Dense‐Stacking Porous Conjugated Polymer as Reactive‐Type Host for High‐Performance Lithium Sulfur Batteries

Abstract

Commercialization of the lithium-sulfur battery is hampered by bottlenecks like lowsulfur loading, high cathode porosity,uncontrollable Li 2 S x deposition and sluggish kinetics of Li 2 Sa ctivation. Herein, we developed ad ensely stacked redox-active hexaazatrinaphthylene (HATN) polymer with asurface area of 302 m 2 g À1 and avery high bulk density of ca. 1.60 gcm À3 .U niquely,H ATNp olymer has as imilar redox potential windowtoS,which facilitates the binding of Li 2 S x and its transformation chemistry within the bulky polymer host, leading to fast Li 2 S/S kinetics.T he compact polymer/S electrode presents ah igh sulfur loading of ca. 15 mg s cm À2 (200-mmt hickness) with al ow cathode porosity of 41 %. It delivers ah igh areal capacity of ca. 14 mAh cm À2 and good cycling stability (200 cycles) at electrolyte-sulfur (E/S) ratio of 5 mLmg s À1 .The assembled pouchcell delivers acell-level high energy density of 303 Wh kg À1 and 392 Wh L À1 .

In Situ Transformation of LDH into NiCo2S4-NiS2 Nano-heterostructures on Hollow Carbon Boxes to Promote Sulfur Electrochemistry for High-Performance Lithium–Sulfur Batteries

“…Compared with lithium-ion batteries, lithium–sulfur batteries have typical advantages in terms of a high theoretical specific capacity (1675 mAh g –1 ), abundant source, environmental friendliness, and low cost. − Benefiting from these advantages, lithium–sulfur batteries are expected to become one of the most promising candidates for future energy storage applications. However, there are several unsolved problems hindering their wide commercial application, including the inferior conductivity of sulfur and Li 2 S/Li 2 S 2 , − notorious “shuttle effect” of soluble lithium polysulfides (LiPS), , and large volume expansion of sulfur upon lithiation (up to 80%). , These issues inevitably lead to the low utilization of sulfur, rapid capacity degradation, limited cycle life, and even some safety problems during practical applications. − …”

Packing Sulfur Species by Phosphorene‐Derived Catalytic Interface for Electrolyte‐Lean Lithium–Sulfur Batteries

“…[9][10][11] Moreover, the highly concentrated LiPS inevitably diffuses to the Li anode that leads to the anode passivation and loss of active materials, and therefore leads to poor cycling stability and low columbic efficiency. [12][13][14] Such pernicious effects due to the slow kinetics are more conspicuous under the practical conditions with high sulfur loading and low electrolyte/sulfur (E/S) ratio for the purpose of achieving high-energy density surpassing current lithium-ion batteries. [15][16][17] Thus, accelerating LiPS conversion by enhancing the electrocatalytic activity of hosts is a promising strategy to achieve exceptional electrochemical performances especially for high-sulfur-loading cathodes with lean electrolyte volume.…”