Angew: Universal Organic Cathode for Ultrafast Lithium and Multivalent Metal Batteries

【introduction】

Since the first commercialization in 1991, lithium-ion batteries (LIBs) have dominated the current energy storage landscape due to their high energy density. However, numerous security incidents, limited resource supply (lithium, cobalt) and high costs seem to limit the large-scale use of the automotive market and fixed energy storage systems. The growing need to integrate intermittent power generation from renewable sources such as solar and wind into the grid requires environmentally friendly/safe, cost-effective, long-lived lithium-ion batteries. Among battery chemistry outside of lithium-ion batteries, magnesium metal batteries (MMBs) and aluminum metal batteries (AMBs) are expected to be used for large-scale energy storage because magnesium and aluminum metals are not only rich and safe, but also impart energy through multi-electron oxidation reduction. . However, their commercialization suffers from poor positive power density and cycle life.

[Introduction]

Recently, the team of Wang Chunsheng (Corresponding author) of the University of Maryland reported a general-purpose polyimide @CNT (PI@CNT) positive electrode, which can reversibly store various cations of different valence states (Li+, Mg2+, Al3+) at extremely fast speed. ). The team system studied the ion coordination charge storage mechanism of PI@CNT. Full cells with PI@CNT positive and corresponding metal negatives have long cycle life (> 10,000 cycles), fast kinetics (> 20 ° C) and wide operating temperature range (-40 ° C to 50 ° C), The polyimide will be a universal positive electrode for different multivalent metal batteries. The stable ion coordination mechanism opens up new ideas for the development of high-energy and high-power multi-valent batteries. Related results were published on Angew under the title "A Universal Organic Cathode for Ultrafast Li- and Multivalent me tal Batteries".

[Graphic introduction]

Figure 1 Schematic diagram of synthesis

(a) Schematic diagram of PI@CNT synthesis

(b) FTIR spectra of synthesized PI@CNTs

(c-f) TEM images (c, d, e) and HRTEM images of PI/CNT composites (f)

Figure 2 Dynamics and quantitative mechanism analysis

(a) Determine the b value using the relationship between the peak current and the scan rate

(b-d) For different valence batteries: (b) LIBs; (c) MMBs; (d) AMBs, capacitance (red region) and diffusion control contribution to charge storage of PI/CNT composites

Figure 3 performance evaluation

(a) Reduction potential and corresponding complexes obtained from quantum chemical (QC) calculations of Li-PI and Mg-PI systems

(b) Applying MBBs to power 50 LED bulbs

【summary】

This working organic polymer solves the serious kinetics and cost of multivalent battery chemicals using inorganic crystalline cathode materials. Current work offers new opportunities for designing multi-charge rechargeable batteries with high power and long cycle life.