Conventional cathodes of Li-ion batteries mainly operate through an insertion-extraction process involving transition metal redox. These cathodes will not be able to meet the increasing requirements until lithium-rich layered oxides emerge with beyond-capacity performance. Nevertheless, in-depth understanding of the evolution of crystal and excess capacity delivered by Li-rich layered oxides is insufficient. Herein, various in situ technologies such as X-ray diffraction and Raman spectroscopy are employed for a typical material Li Ni Mn O , directly visualizing O O (peroxo oxygen dimers) bonding mostly along the c-axis and demonstrating the reversible O /O redox process. Additionally, the formation of the peroxo OO bond is calculated via density functional theory, and the corresponding OO bond length of ≈1.3 Å matches well with the in situ Raman results. These findings enrich the oxygen chemistry in layered oxides and open opportunities to design high-performance positive electrodes for lithium-ion batteries.

Solid-state lithium batteries are widely considered as next-generation lithiumion battery technology due to the potential advantages in safety and performance. Among the various solid electrolyte materials, Li-garnet electrolytes are promising due to their high ionic conductivity and good chemical and electrochemical stabilities. However, the high electrode/electrolyte interfacial impedance is one of the major challenges. Moreover, short circuiting caused by lithium dendrite formation is reported when using Li-garnet electrolytes. Here, it is demonstrated that Li-garnet electrolytes wet well with lithium metal by removing the intrinsic impurity layer on the surface of the lithium metal. The Li/garnet interfacial impedance is determined to be 6.95 Ω cm 2 at room temperature. Lithium symmetric cells based on the Li-garnet electrolytes are cycled at room temperature for 950 h and current density as high as 13.3 mA cm −2 without showing signs of short circuiting. Experimental and computational results reveal that it is the surface oxide layer on the lithium metal together with the garnet surface that majorly determines the Li/garnet interfacial property. These findings suggest that removing the superficial impurity layer on the lithium metal can enhance the wettability, which may impact the manufacturing process of future high energy density garnet-based solid-state lithium batteries. are gratefully acknowledged for assisting with relevant experimental analysis. Center for High Performance Computing of SJTU is gratefully acknowledged for providing computational facilities for all the simulations. Conflict of InterestThe authors declare no conflict of interest.

Increased generation of spent lithium-ion batteries (LIBs) has driven the exploration of new methods for reusing and/or recycling LiCoO2 cathode materials. Herein, an electrochemical relithiation method was proposed to directly regenerate LiCoO2 cathode materials using the waste Li x CoO2 electrode as a base. It was shown that Li+ was successfully inserted into the waste Li x CoO2 electrode, and this relithiation process became faster with either a higher Li2SO4 concentration or a higher cathodic current density. The XRD analysis confirmed that the peak positions of the relithiation products were consistently close to those of a standard LiCoO2 material. The crystal structure of the relithiation products was restored with a post-annealing process. The activation energy for electrochemical relithiation (E a) was estimated at 22 kJ mol–1, and the constant of equilibrium constant k 0 was determined as 1.35 × 10–6 cm s–1. The relithiation process was controlled by the charge transfer process when the Li2SO4 concentration was high (e.g., 1, 0.8, and 0.5M), and a lower concentration at 0.01–0.3 M led to a diffusion control pattern. The electrode made of the regenerated LiCoO2 materials had a charge capacity of 136 mAh g–1, close to that of the commercial LiCoO2 electrode (140 mAh g–1). A potential mechanism of electrochemical relithiation was proposed involving lithium defects, relithiation, and crystal regeneration.

Alongside the steep reductions needed in fossil fuel emissions, natural climate solutions (NCS) represent readily deployable options that can contribute to Canada’s goals for emission reductions. We estimate the mitigation potential of 24 NCS related to the protection, management, and restoration of natural systems that can also deliver numerous co-benefits, such as enhanced soil productivity, clean air and water, and biodiversity conservation. NCS can provide up to 78.2 (41.0 to 115.1) Tg CO2e/year (95% CI) of mitigation annually in 2030 and 394.4 (173.2 to 612.4) Tg CO2e cumulatively between 2021 and 2030, with 34% available at ≤CAD 50/Mg CO2e. Avoided conversion of grassland, avoided peatland disturbance, cover crops, and improved forest management offer the largest mitigation opportunities. The mitigation identified here represents an important potential contribution to the Paris Agreement, such that NCS combined with existing mitigation plans could help Canada to meet or exceed its climate goals.