All-cellulose gel electrolyte with black phosphorus based lithium ion conductors toward advanced lithium-sulfurized polyacrylonitrile batteries.

Sulfurized polyacrylonitrile (SPAN) have been regarded as a promising cathode in high-energy-density lithium-sulfur batteries. However, severe safety issues derived from the electrolyte leakage and the uncontrollable lithium dendrite growth have seriously hindered the practical usage of Li-SPAN batteries. To address these issues, an eco-friendly and porous cellulose gel electrolyte (GE) was designed and prepared by UV photopolymerization and phase inversion methods. Also, covalent functional black phosphorous nanosheets (denoted as BP-Li) were fabricated and chosen as superior Li+ conductors in cellulose GE, ensuring the rapid ion transmission and suppressing the growth of lithium dendrites. As expected, the cellulose/BP-Li GE exhibited satisfactory ionic conductivity up to 5.21 × 10-3 S cm-1 with the high lithium ion transference number of 0.72. The Li-SPAN battery assembled with cellulose/BP-Li GE delivered high capacity of 938.8 mAh g-1 after 500 cycles with the capacity retention of 72.8 %. Hence, the cellulose/BP-Li GE displayed its promising usage in Li-SPAN batteries.

Huang Y ，Wang Y ，Fu Y 《-》

Electrolyte Regulation towards Stable Lithium-Metal Anodes in Lithium-Sulfur Batteries with Sulfurized Polyacrylonitrile Cathodes.

Lithium-sulfur (Li-S) batteries are highly regarded as the next-generation energy-storage devices because of their ultrahigh theoretical energy density of 2600 Wh kg-1 . Sulfurized polyacrylonitrile (SPAN) is considered a promising sulfur cathode to substitute carbon/sulfur (C/S) composites to afford higher Coulombic efficiency, improved cycling stability, and potential high-energy-density Li-SPAN batteries. However, the instability of the Li-metal anode threatens the performances of Li-SPAN batteries bringing limited lifespan and safety hazards. Li-metal can react with most kinds of electrolyte to generate a protective solid electrolyte interphase (SEI), electrolyte regulation is a widely accepted strategy to protect Li-metal anodes in rechargeable batteries. Herein, the basic principles and current challenges of Li-SPAN batteries are addressed. Recent advances on electrolyte regulation towards stable Li-metal anodes in Li-SPAN batteries are summarized to suggest design strategies of solvents, lithium salts, additives, and gel electrolyte. Finally, prospects for future electrolyte design and Li anode protection in Li-SPAN batteries are discussed.

Chen WJ ，Li BQ ，Zhao CX ，Zhao M ，Yuan TQ ，Sun RC ，Huang JQ ，Zhang Q ... -  《-》

Simultaneously Suppressing Shuttle Effect and Dendrite Growth in Lithium-Sulfur Batteries via Building Dual-Functional Asymmetric-Cellulose Gel Electrolyte.

Polysulfides huttling and interfacial instability of Lithium-anode are the main technical issues hindering commercialization of high-energy-density lithium-sulfur batteries. Simply addressing the problem of polysulfide shuttling or lithium dendrite growth can result in safety hazards or short lifespan. To synchronously tackle the aforementioned issues, the authors have designed an asymmetric cellulose gel electrolyte, a defective and ionized UiO66/black phosphorus heterostructure coating layer (Di-UiO66/BP) and a cationic cellulose gelelectrolyte (QACA). Defective and ionized engineered UiO66 particles significantly enhances performance of UiO66/BP layer in anchoring free polysulfides, promoting smooth and effective polysulfide conversion and expediting the redox kinetics of sulfur cathode, therefore suppressing polysulfide shuttling. QACA electrolyte with numerous cationic groups can interact with anions via electrostatic adsorption, thus enhancing lithium-ion transference number and contributing to formation of stable solid electrolyte interface to suppress lithium dendrite growth. Owing to the superior performance of QACA/Di-UiO66/BP, the final cells exhibit outstanding electrochemical performance, presenting high sulfur utilization (1420.1 mAh g-1 at 0.1 C), high-rate capacity (665.4 mAh g-1 at 4 C) and long cycle lifespan. This work proposes a strategy of designing asymmetric electrolytes to simultaneously address the challenges in both S-cathode and Li-anode, which contributes to advanced Li-S batteries and their practical application.

Huang Y ，Cheng F ，Cai C ，Fu Y ... -  《-》

Pinned Electrode/Electrolyte Interphase and Its Formation Origin for Sulfurized Polyacrylonitrile Cathode in Stable Lithium Batteries.

Zhang X ，Gao P ，Wu Z ，Engelhard MH ，Cao X ，Jia H ，Xu Y ，Liu H ，Wang C ，Liu J ，Zhang JG ，Liu P ，Xu W ... -  《-》

Reversible Solid-Solid Conversion of Sulfurized Polyacrylonitrile Cathodes in Lithium-Sulfur Batteries by Weakly Solvating Ether Electrolytes.

Despite carbonate electrolytes exhibiting good stability to sulfurized polyacrylonitrile (SPAN), their chemical incompatibility with lithium (Li) metal anode leads to poor electrochemical performance of Li||SPAN full cells. While the SPAN employs conventional ether electrolytes that suffer from the shuttle effect, leading to rapid capacity fading. Here, we tailor a dilute electrolyte based on a low solvating power ether solvent that is both compatible with SPAN and Li metal. Unlike conventional ether electrolytes, the weakly solvating ether electrolyte enables SPAN to undergo reversibly "solid-solid" conversion. It features an anion-rich solvation structure that allows for the formation of a robust cathode electrolyte interphase on the SPAN, effectively blocking the dissolution of polysulfides into the bulk electrolyte and avoiding the shuttle effect. What's more, the unique electrolyte chemistry endowed Li ions with fast electroplating kinetics and induced high reversibility Li deposition/stripping process from 25 °C to -40 °C. Based on tailored electrolyte, Li||SPAN full cells matched with high loading SPAN cathodes (≈3.6 mAh cm-2 ) and 50 μm Li foil can operate stably over a wide range of temperatures. Additionally, Li||SPAN pouch cell under lean electrolyte and 5 % excess Li conditions can continuously operate stably for over a month.

Ma T ，Ni Y ，Li D ，Zha Z ，Jin S ，Zhang W ，Jia L ，Sun Q ，Xie W ，Tao Z ，Chen J ... -  《-》