The demand for sustainable green energy and quality of life has become more urgent as modern society and industry move forward at full speed. This has further promoted the shift of society to environmental and sustainable development. [1,2] The emergence of LIBs has greatly mitigated the major petroleum-fuel pollution and energy crises, and is also a good replacement for certain new energy sources, with uncertain characteristics and intermittent properties including tidal energy, solar, hydroelectric, nuclear, and wind power developed. [3] In the 1990s, Sony commercialized LIBs successfully. [1] Using their unique advances, including high power density, no storage, small size, light weight, long cycle life, and low self-discharge rates, LIBs have so far gathered enormous market share following 30 years of development and progress in the sector. [1,4] It is widely used in electronic consumer, medical, electric vehicle, the industry, aerospace and defense, power storage, and other industries. [5] Moreover, the battery market of lithium-ion is currently undergoing major changes and LIBs are expected to grow over hundreds of gigawatt hours per year worldwide in the next five years and to account for 70% of the battery rechargeable market in 2025. [6] The global demand for lithium batteries in 2018 is 231 326 billion Yuan and the volume of shipments is 146.38 GWh, according to the prediction of the relevant research institutions of the industry. The demand for the market in lithium batteries is going to reach 694 265 billion yuan in particular, with a market capacity of 439.32 GWh in 2025. Driven by the continuous electrification of the auto industry, LIBs have reached millions of trading volumes as the main driver of electric vehicles and hybrid vehicles will continue to grow in the future. [7,8] The global market for LIBs is estimated to be around US $40 billion by 2025, and more than a third is expected to come from the hybrid and electric vehicle markets. [9] In the face of these massive volumes of LIBs, all demands have promoted the production of a large number of LIBs, which have led to large production shortages, in particular metal resources such as lithium and cobalt. [10,11] LIBs in electric vehicles have a life span of only 5-10 years, while small electronic products have a lifetime almost 3 years. [12,13] Therefore, in the face of the explosive growth and of such a substantial amount of rechargeable LIBs, generous LIBs will be scrapped in the immediate future. It is speculated that China alone can produce 500 000 metric tons of used LIBs in 2020, and the world is expected to process 11 million tons of spent LIBs by 2030. [12,14] However, the high metal content of waste LIB is an important metal resource, especially because global reserves are limited to approximately 62 million tons of Li and 145 million tons of Co. The supply of these raw materials from natural resources will not be able to meet future demand.

Covalent organic frameworks (COF) possess a robust and porous crystalline structure, making them an appealing candidate for energy storage. Herein, we report an exfoliated polyimide COF composite (P‐COF@SWCNT) prepared by an in situ condensation of anhydride and amine on the single‐walled carbon nanotubes as advanced anode for potassium‐ion batteries (PIBs). Numerous active sites exposed on the exfoliated frameworks and the various open pathways promote the highly efficient ion diffusion in the P‐COF@SWCNT while preventing irreversible dissolution in the electrolyte. During the charging/discharging process, K+ is engaged in the carbonyls of imide group and naphthalene rings through the enolization and π‐K+ effect, which is demonstrated by the DFT calculation and XPS, ex‐situ FTIR, Raman. As a result, the prepared P‐COF@SWCNT anode enables an incredibly high reversible specific capacity of 438 mA h g−1 at 0.05 A g−1 and extended stability. The structural advantage of P‐COF@SWCNT enables more insights into the design and versatility of COF as an electrode.

Along with the explosive growth in the market of new energy electric vehicles, the demand for Li-ion batteries (LIBs) has correspondingly expanded. Given the limited life of LIBs, numbers of spent LIBs are bound to be produced. Because of the severe threats and challenges of spent LIBs to the environment, resources, and global sustainable development, the recycling and reuse of spent LIBs have become urgent. Herein, we propose a novel green and efficient direct recycling method, which realizes the concurrent reuse of LiFePO 4 (LFP) cathode and graphite anode from spent LFP batteries. By optimizing the proportion of LFP and graphite, a hybrid LFP/ graphite (LFPG) cathode was designed for a new type of dualion battery (DIB) that can achieve co-participation in the storage of both anions and cations. The hybrid LFPG cathode combines the excellent stability of LFP and the high conductivity of graphite to exhibit an extraordinary electrochemical performance. The best compound, i.e., LFP:graphite = 3:1, with the highest reversible capacity (~130 mA h g −1 at 25 mA g −1 ), high voltage platform of 4.95 V, and outstanding cycle performance, was achieved. The specific diffusion behavior of Li + and PF 6 − in the hybrid cathode was studied using electrode kinetic tests, further clarifying the working mechanism of DIBs. This study provides a new strategy toward the large-scale recycling of positive and negative electrodes of spent LIBs and establishes a precedent for designing new hybrid cathode materials for DIBs with superior performance using spent LIBs.

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As the power supply of the prosperous new energy products, advanced lithium ion batteries (LIBs) are widely applied to portable energy equipment and large‐scale energy storage systems. To broaden the applicable range, considerable endeavours have been devoted towards improving the energy and power density of LIBs. However, the side reaction caused by the close contact between the electrode (particularly the cathode) and the electrolyte leads to capacity decay and structural degradation, which is a tricky problem to be solved. In order to overcome this obstacle, the researchers focused their attention on electrolyte additives. By adding additives to the electrolyte, the construction of a stable cathode‐electrolyte interphase (CEI) between the cathode and the electrolyte has been proven to competently elevate the overall electrochemical performance of LIBs. However, how to choose electrolyte additives that match different cathode systems ideally to achieve stable CEI layer construction and high‐performance LIBs is still in the stage of repeated experiments and exploration. This article specifically introduces the working mechanism of diverse electrolyte additives for forming a stable CEI layer and summarizes the latest research progress in the application of electrolyte additives for LIBs with diverse cathode materials. Finally, we tentatively set forth recommendations on the screening and customization of ideal additives required for the construction of robust CEI layer in LIBs. We believe this minireview will have a certain reference value for the design and construction of stable CEI layer to realize desirable performance of LIBs.