High Voltage Carbon‐Based Cathodes for Non‐Aqueous Aluminium‐Ion Batteries**

Ultrahigh Capacity from Complexation-Enabled Aluminum-Ion Batteries with C70 as the Cathode

Restricted by the available energy storage modes, currently rechargeable aluminum-ion batteries (RABs) can only provide a very limited experimental capacity, regardless of the very high gravimetric capacity of Al (2980 mAh g-1 ). Here, a novel complexation mechanism is reported for energy storage in RABs by utilizing 0D fullerene C70 as the cathode. This mechanism enables remarkable discharge voltage (≈1.65 V) and especially a record-high reversible specific capacity (750 mAh g-1 at 200 mA g-1 ) of RABs. By means of in situ Raman monitoring, mass spectrometry, and density functional theory (DFT) calculations, it is found that this elevated capacity is attributed to the direct complexation of one C70 molecule with 23.5 (super)halogen moieties (superhalogen AlCl4 and/or halogen Cl) in average, forming (super)halogenated C70 ·(AlCl4 )m Cln-m complexes. Upon discharging, decomplexation of C70 ·(AlCl4 )m Cln-m releases AlCl4 - /Cl- ions while preserving the intact fullerene cage. This work provides a new route to realize high-capacity and long-life batteries following the complexation mechanism.

Sustainable Biomass-Derived Carbon Electrodes for Potassium and Aluminum Batteries: Conceptualizing the Key Parameters for Improved Performance

The development of sustainable, safe, low-cost, high energy and density power-density energy storage devices is most needed to electrify our modern needs to reach a carbon-neutral society by ~2050. Batteries are the backbones of future sustainable energy sources for both stationary off-grid and mobile plug-in electric vehicle applications. Biomass-derived carbon materials are extensively researched as efficient and sustainable electrode/anode candidates for lithium/sodium-ion chemistries due to their well-developed tailored textures (closed pores and defects) and large microcrystalline interlayer spacing and therefore opens-up their potential applications in sustainable potassium and aluminum batteries. The main purpose of this perspective is to brief the use of biomass residues for the preparation of carbon electrodes for potassium and aluminum batteries annexed to the biomass-derived carbon physicochemical structures and their aligned electrochemical properties. In addition, we presented an outlook as well as some challenges faced in this promising area of research. We believe that this review enlightens the readers with useful insights and a reasonable understanding of issues and challenges faced in the preparation, physicochemical properties and application of biomass-derived carbon materials as anodes and cathode candidates for potassium and aluminum batteries, respectively. In addition, this review can further help material scientists to seek out novel electrode materials from different types of biomasses, which opens up new avenues in the fabrication/development of next-generation sustainable and high-energy density batteries.