Strategies to Realize Compact Energy Storage for Lithium-Sulfur Batteries

High volume energy density(Ev)means more energy can be stored in a small space,which helps ease the“space anxiety”faced by electrochemical energy storage(EES)devices such as batteries.Lithium-sulfur batteries(LSBs)are promising next-generation EES devices due to their high theoretical energy density.However,its E_(v) is unsatisfactory due to the low density of sulfur and excess use of lightweight nanocarbon in the cathode,severely limiting its practical applications.In this review,the recent progress in improving the E_(v) is summarized from the aspects of materials,electrodes,and devices.First,the key factors affecting E_(v) are discussed.Then at the material level,the design of materials with high density and rich pore structure,and the key roles of catalysts are discussed.At the electrode level,the design of the compact electrode structure is summarized.Increasing the thickness of the cathodes or reducing the use of the anodes(low N/P ratio)to improve E_(v) from the device level is highlighted.Finally,the E_(v) of solid-state LSBs system has been prospected.

Design and modification of metal sulfide-based catalysts for lithiumsulfur batteries

Metal sulfide(MS)have good conductivity,strong adsorption ability,and excellent catalytic activity for the conversion of sulfur species,and thus,show great promise as the catalysts in LieS batteries.However,the relationship between their properties and electrochemical performance is still unclear.Thus,further in-depth discussions are required to improve their design in Li-S batteries.This review systematically summarizes the basic structural and electrochemical properties of MSs and highlights the advantages that guarantee them as high-performance catalysts in Li-S batteries.Then,various modification strategies for MSs to enhance the catalytic activity,efficiency,and stability are also reviewed.At last,future opportunities for MS catalysts in Li-S batteries are proposed.

Unveiling multi-element synergy in polymetallic oxides for efficient nitrate reduction to ammonia

Electrocatalytic nitrate reduction reaction is considered as a promising and sustainable method for ammonia synthesis.However,the selectivity and yield rate of ammonia are limited by the competitive hydrogen evolution reaction and the complex eight-electron transfer process.Herein,we developed a(FeCoNiCu)Ox/CeO_(2)polymetallic oxide electrocatalyst for effective nitrate reduction to ammonia.The synergistic effects among the multiple elements in the electrocatalyst were clearly elucidated by comprehensive experiments.Specifically,Cu acted as the active site for reducing nitrate to nitrite,and Co facilitated the subsequent reduction of nitrite to ammonia,while Fe and Ni promoted water dissociation to provide protons.Furthermore,the incorporation of CeO_(2)increased the active surface area of(FeCoNiCu)Ox,resulting in an improved ammonia yield rate to meet industrial demands.Consequently,the(FeCoNiCu)Ox/CeO_(2)electrocatalyst achieved an ammonia current density of 382 mA cm^(-2)and a high ammonia yield rate of 30.3 mg h^(-1)cm^(-2)with a long-term stability.This work offers valuable insights for the future design of highly efficient multi-element electrocatalysts.

电子轴向拉伸提升贫氧环境海水电池性能

长寿命溶解氧海水电池是深远海观测能源网络的重要组成单元,但海水贫氧复杂环境对设计高性能氧还原催化剂提出了重要挑战.本文以酞菁铁为模型催化剂,通过理论计算与实验验证,提出了活性位点电子轴向拉伸可大幅提升催化剂在极端贫氧环境中的氧还原活性和稳定性.该研究为构建高性能海水电池提供了材料学解决方案,同时为极端环境下催化剂的变革性设计提供了新的思路.