Black Anatase Titania with Ultrafast Sodium-Storage Performances Stimulated by Oxygen Vacancies

Nanostructured black anatase titania with oxygen vacancies (OVs) is efficiently obtained and employed as an anode in sodium-ion batteries (SIBs) for the first time. The incorporation of OVs into TiO₂ is demonstrated to render considerably enhanced-rate performances, higher initial capacities, and an accelerated electrochemical activation process during cycling, derived from the boosted intrinsic electric conductivity and improved kinetics of Na uptake. Bestowed with the integrated merits of OVs and shortened Na ion diffusion length in the nanostructure, black titania delivers a reversible specific capacity of 207.6 mAh g^–1 at 0.2 C, retains 99.1% over 500 cycles at 1 C stably, and still maintains 91.2 mAh g^–1 even at the high rate of 20 C. Density functional theory (DFT) calculations suggest that the lower sodiation energy barrier of anatase with OVs enables a more favorable Na intercalation into black anatase. Thus, it is of great significance to introduce OVs into TiO₂ to stimulate ultrafast and durable sodium-storage properties, which also offers a potential strategy to project more superior electrodes, utilizing internal defects

Redox-Mediated Recycling of Spent Lithium-Ion Batteries Coupled with Low-Energy Consumption Hydrogen Production

Electrochemical recycling of spent lithium-ion batteries (sLIBs) is potentially cost-effective and consumes fewer chemicals than traditional metallurgical processes. However, severe side reactions and low system durability limit its practical applications. Herein, a redox-mediated electrochemical recycling strategy was developed for continuous Li extraction from spent LiFePO4 (sLFP), coupled with low-energy-consumption hydrogen production. Phosphomolybdic acid (PMA) was employed as a green redox mediator to achieve fast and selective Li extraction from sLFP, and the reduced PMA was instantaneously electro-regenerated for subsequent extractions. In the assembled electrochemical flow cell, the Li recovery efficiency reached 97.8%, and the Faradaic efficiency of the hydrogen evolution reaction was approximately 100%. Furthermore, the redox-mediated sLFP-hydrogen coupling system required only 0.5 V of cell voltage to produce hydrogen, significantly lower than that of ∼1.65 V in the traditional water splitting process. This work presents a promising and sustainable route for the simultaneous recycling of sLIB and production of clean hydrogen fuels

Redox-Mediated Recycling of Spent Lithium-Ion Batteries Coupled with Low-Energy Consumption Hydrogen Production

Electrochemical recycling of spent lithium-ion batteries (sLIBs) is potentially cost-effective and consumes fewer chemicals than traditional metallurgical processes. However, severe side reactions and low system durability limit its practical applications. Herein, a redox-mediated electrochemical recycling strategy was developed for continuous Li extraction from spent LiFePO4 (sLFP), coupled with low-energy-consumption hydrogen production. Phosphomolybdic acid (PMA) was employed as a green redox mediator to achieve fast and selective Li extraction from sLFP, and the reduced PMA was instantaneously electro-regenerated for subsequent extractions. In the assembled electrochemical flow cell, the Li recovery efficiency reached 97.8%, and the Faradaic efficiency of the hydrogen evolution reaction was approximately 100%. Furthermore, the redox-mediated sLFP-hydrogen coupling system required only 0.5 V of cell voltage to produce hydrogen, significantly lower than that of ∼1.65 V in the traditional water splitting process. This work presents a promising and sustainable route for the simultaneous recycling of sLIB and production of clean hydrogen fuels