• Energy Research
• Carbon Energy close

AbstractA solid‐state electrolyte (SSE), which is a solid ionic conductor and electron‐insulating material, is known to play a crucial role in adapting a lithium metal anode to a high‐capacity cathode in a solid‐state battery. Among the various SSEs, the single Li‐ion conductor has advantages in terms of enhancing the ion conductivity, eliminating interfacial side reactions, and broadening the electrochemical window. Covalent organic frameworks (COFs) are optimal platforms for achieving single Li‐ion conduction behavior because of well‐ordered one‐dimensional channels and precise chemical modification features. Herein, we study in depth three types of Li‐carboxylate COFs (denoted LiOOC‐COFn, n = 1, 2, and 3) as single Li‐ion conducting SSEs. Benefiting from well‐ordered directional ion channels, the single Li‐ion conductor LiOOC‐COF3 shows an exceptional ion conductivity of 1.36 × 10−5 S cm−1 at room temperature and a high transference number of 0.91. Moreover, it shows excellent electrochemical performance with long‐term cycling, high‐capacity output, and no dendrites in the quasi‐solid‐state organic battery, with the organic small molecule cyclohexanehexone (C6O6) as the cathode and the Li metal as the anode, and enables effectively avoiding dissolution of the organic electrode by the liquid electrolyte.

AbstractA solid‐state electrolyte (SSE), which is a solid ionic conductor and electron‐insulating material, is known to play a crucial role in adapting a lithium metal anode to a high‐capacity cathode in a solid‐state battery. Among the various SSEs, the single Li‐ion conductor has advantages in terms of enhancing the ion conductivity, eliminating interfacial side reactions, and broadening the electrochemical window. Covalent organic frameworks (COFs) are optimal platforms for achieving single Li‐ion conduction behavior because of well‐ordered one‐dimensional channels and precise chemical modification features. Herein, we study in depth three types of Li‐carboxylate COFs (denoted LiOOC‐COFn, n = 1, 2, and 3) as single Li‐ion conducting SSEs. Benefiting from well‐ordered directional ion channels, the single Li‐ion conductor LiOOC‐COF3 shows an exceptional ion conductivity of 1.36 × 10−5 S cm−1 at room temperature and a high transference number of 0.91. Moreover, it shows excellent electrochemical performance with long‐term cycling, high‐capacity output, and no dendrites in the quasi‐solid‐state organic battery, with the organic small molecule cyclohexanehexone (C6O6) as the cathode and the Li metal as the anode, and enables effectively avoiding dissolution of the organic electrode by the liquid electrolyte.

ABSTRACTAdvanced oxygen carrier plays a pivotal role in various chemical looping processes, such as CO2 splitting. However, oxygen carriers have been restricted by deactivation and inferior oxygen transferability at low temperatures. Herein, we design an Fe–Ov–Ce–triggered phase‐reversible CeO2−x·Fe·CaO ↔ CeO2·Ca2Fe2O5 oxygen carrier with strong electron‐donating ability, which activates CO2 at low temperatures and promotes oxygen transformation. Results reveal that the maximum CO2 conversion and CO yield obtained with 50 mol% CeO2−x·Fe·CaO are, respectively, 426% and 53.6 times higher than those of Fe·CaO at 700°C. This unique multiphase material also retains exceptional redox durability, with no obvious deactivation after 100 splitting cycles. The addition of Ce promotes the formation of the Fe–Ov–Ce structure, which acts as an activator, triggers CO2 splitting, and lowers the energy barrier of C═O dissociation. The metallic Fe plays a role in consuming O2−lattice transformed from Fe–Ov–Ce, whereas CaO acts as a structure promoter that enables phase‐reversible Fe0 ↔ Fe3+ looping.

ABSTRACTAdvanced oxygen carrier plays a pivotal role in various chemical looping processes, such as CO2 splitting. However, oxygen carriers have been restricted by deactivation and inferior oxygen transferability at low temperatures. Herein, we design an Fe–Ov–Ce–triggered phase‐reversible CeO2−x·Fe·CaO ↔ CeO2·Ca2Fe2O5 oxygen carrier with strong electron‐donating ability, which activates CO2 at low temperatures and promotes oxygen transformation. Results reveal that the maximum CO2 conversion and CO yield obtained with 50 mol% CeO2−x·Fe·CaO are, respectively, 426% and 53.6 times higher than those of Fe·CaO at 700°C. This unique multiphase material also retains exceptional redox durability, with no obvious deactivation after 100 splitting cycles. The addition of Ce promotes the formation of the Fe–Ov–Ce structure, which acts as an activator, triggers CO2 splitting, and lowers the energy barrier of C═O dissociation. The metallic Fe plays a role in consuming O2−lattice transformed from Fe–Ov–Ce, whereas CaO acts as a structure promoter that enables phase‐reversible Fe0 ↔ Fe3+ looping.

AbstractThe typical metal chloride‐graphite intercalation compounds (MC‐GICs) inherit intercalation capacity, high charge conductivity, and high tap density from graphite, and these are considered as one of the promising alternatives of graphite anode in rechargeable metal‐ion batteries (MIBs). Notably, the special interlayer decoupling effects and the introduction of extra conversion capacity by metal chloride could greatly break the capacity limitation of graphite anodes and achieve higher energy density in MIBs. The optimization of both graphite host and metal chloride species with specific structures endows MC‐GICs with design feasibility for different application requirements of different MIBs, such as several times the actual capacity compared to graphite anodes, rapid migration of large carriers, and other properties. Herein, a brief review has been provided with the latest understanding of conductivity characteristics and energy storage mechanisms of MC‐GICs and their interesting performance features of full potential application in rechargeable MIBs. Based on the existing research of MC‐GICs, necessary improvements and prospects in the near future have been put forward.

AbstractThe typical metal chloride‐graphite intercalation compounds (MC‐GICs) inherit intercalation capacity, high charge conductivity, and high tap density from graphite, and these are considered as one of the promising alternatives of graphite anode in rechargeable metal‐ion batteries (MIBs). Notably, the special interlayer decoupling effects and the introduction of extra conversion capacity by metal chloride could greatly break the capacity limitation of graphite anodes and achieve higher energy density in MIBs. The optimization of both graphite host and metal chloride species with specific structures endows MC‐GICs with design feasibility for different application requirements of different MIBs, such as several times the actual capacity compared to graphite anodes, rapid migration of large carriers, and other properties. Herein, a brief review has been provided with the latest understanding of conductivity characteristics and energy storage mechanisms of MC‐GICs and their interesting performance features of full potential application in rechargeable MIBs. Based on the existing research of MC‐GICs, necessary improvements and prospects in the near future have been put forward.

AbstractLithium metal batteries with inorganic solid‐state electrolytes have emerged as strong and attractive candidates for electrochemical energy storage devices because of their high‐energy content and safety. Nonetheless, inherent challenges of deleterious lithium dendrite growth and poor interfacial stability hinder their commercial application. Herein, we report a liquid metal‐coated lithium metal (LM@Li) anode strategy to improve the contact between lithium metal and a Li6PS5Cl inorganic electrolyte. The LM@Li symmetric cell shows over 1000 h of stable lithium plating/stripping cycles at 2 mA cm−2 and a significantly higher critical current density of 9.8 mA cm−2 at 25°C. In addition, a full battery assembled with a high‐capacity composite LiNbO3@LiNi0.7Co0.2Mn0.1O2 (LNO@NCM721) cathode shows stable cycling performance. Experimental and computational results have demonstrated that dendrite growth tolerance and physical contact in solid‐state batteries can be reinforced by using LM interlayers for interfacial modification.