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The Ti3C2Tx MXene with surface functional groups complexing Mn4+ (Mn–Ti3C2Tx) was prepared for the cathode of aqueous zinc batteries. The electrode reaction is confirmed as the Zn2+/H+ co-insertion compensated by the Mn4+/Mn2+ redox. The Mn4+-loading modification boosts the Zn2+ storage due to the enhanced Zn2+ adsorption possibility. [ABSTRACT FROM AUTHOR]

Aluminum batteries (ABs) have been considered as a viable candidate for new‐generation energy‐storage devices due to its low cost and high theoretical volumetric capacity. Despite these advantages, the large‐scale application of ABs is constrained by scarce options of suitable cathode materials. Herein, three‐dimensional nanostructured α‐MnSe microspheres with porous properties are reported as a cathode for ABs. The nanosized and porous structure of α‐MnSe could offer numerous open channels and the short ionic transport path, which would efficiently mitigate volume changes and enhance electrochemical reaction kinetics. Moreover, the pseudocapacitive characteristic of Al3+ storage in α‐MnSe contributes to the fast kinetics of the cathode. It is demonstrated that the reversible Al3+ insertion/extraction occurs in the α‐MnSe cathode during the cycling process. The resulting aluminum battery based on the α‐MnSe cathode, AlCl3/[EMIm]Cl ionic liquid electrolyte, and aluminum anode exhibits an ultrahigh reversible capacity of 408 mA h g−1 at 0.2 A g−1. Even for a current density at 1 A g−1, a discharge capacity of 131 mA h g−1 could be retained with a Coulombic efficiency of 97 % over 150 cycles. This strategy has referential significance in aspects of the selection of compatible cathode for ABs. [ABSTRACT FROM AUTHOR]

AlP-modified LiMn 2 O 4 has been synthesized via a simple chemical deposition method followed by high-temperature heating. The X-ray diffraction patterns, SEM images and Energy Dispersive Spectrometer show the successful surface coating of LiMn 2 O 4 by F-43 m crystal form AlP. AlP-modified LiMn 2 O 4 has a high discharge capacity of 125.7 mAh g −1 with retention of 87% at a current density of 1C between 3.3 V and 4.3 V after 100 cycles at 60 °C, while bare LiMn 2 O 4 has more than 28% capacity loss. At 10 rates, the coated sample delivers capacity of 100 mAh g −1 , which is much higher than bare LiMn 2 O 4 . Based on the EIS (electrochemical impedance spectroscopy) result, AlP coating can effectively inhibit the increase of the charge transfer resistance during charging and discharging cycles. [ABSTRACT FROM AUTHOR]

LiMn 2 O 4 spinel cathode materials were modified with 1%, 3% and 5% Co 3 (PO 4 ) 2 coating with a simple chemical deposition process, followed by calcinations at 420 °C for 3 h in air. The Co 3 (PO 4 ) 2 surface modified samples showed much better capacity retention at both room temperature and 60 °C than bare LiMn 2 O 4 . Especially, 3 wt.% Co 3 (PO 4 ) 2 coated sample exhibited superior capacity retention with only 12% capacity loss after 100 cycles at 60 °C with a final capacity around 110 mAh g − 1 . From the electrochemical impedance spectroscopy (EIS) analysis, Co 3 (PO 4 ) 2 surface coating suppressed the undesirable growth of electrochemical impedance spectroscopy (SEI). The cyclic voltammetry (CV) confirmed that Co 3 (PO 4 ) 2 surface modification improved the stability of the LiMn 2 O 4 structure. Therefore, Co 3 (PO 4 ) 2 will be a promising coating material for LiMn 2 O 4 to improve the cyclic performance. [ABSTRACT FROM AUTHOR]

• Heterostructured g-C 3 N 4 /Ti 3 C 2 T x endows electrode with enhanced structural stability and fast charge transfer. • The heterostructured g-C 3 N 4 /Ti 3 C 2 T x delivers superior aluminum-storage performance. • The charge-discharge mechanism for g-C 3 N 4 /Ti 3 C 2 T x is reversible intercalation of chloroaluminate anions. [Display omitted] As a compelling complement to lithium batteries, rechargeable aluminum batteries (RABs) have attracted considerable attention because of abundant natural resources, high volumetric capacity, and safety property of aluminum metal. However, the deployment of RABs is hampered by the lack of favorable cathodes with high capacity and rapid kinetics. To address the long-unresolved issue of aluminum-storage capacity and rate, here we design a heterostructured g-C 3 N 4 /Ti 3 C 2 T x hybrid which offers a conductive supporting framework to maintain structural integrity and accelerate electronic transport. The energy storage mechanism of the heterostructured g-C 3 N 4 /Ti 3 C 2 T x cathode was demonstrated as the reversible intercalation of AlCl 4 − during cycling. Moreover, the battery-capacitance model mechanism in the heterostructured g-C 3 N 4 /Ti 3 C 2 T x hybrids may accelerate the kinetics of the electrode reactions. Furthermore, DFT calculations certify that heterostructured g-C 3 N 4 /Ti 3 C 2 T x possesses enhanced electrical conductivity and Al trapping capability. Accordingly, the heterostructured g-C 3 N 4 /Ti 3 C 2 T x cathode affords RABs with an excellent Al-storage property (237 mAh g-1 at 0.5 A g-1) and considerable rate capabilities (174 mAh g-1 at 4 A g-1) among state-of-the-art cathode materials for aluminum batteries. [ABSTRACT FROM AUTHOR]

• A novel Al-ion battery based on a room temperature electrolyte was assembled. • AlCl 3 /pyridinium chloride (PC) was firstly used as the electrolyte for Al-ion battery. • Spherical graphite is firstly used as the cathode for Al-ion battery. • The battery performs a discharge capacity of 123 mA h g−1 at 1 A g−1. The electrolyte system of Al-ion batteries still faces some problems, such as high price, low capacity and strict working environment. Here, a novel ionic liquid AlCl 3 /pyridinium chloride (PC) is prepared as the electrolyte for Al-ion battery, and spherical graphite (SG) is also firstly used as the cathode. The battery performs a discharge capacity of 123 mA h g−1 at the current density of 1 A g−1. It can reach 101 mA h g−1 at 5 A g−1 with a good coulombic efficiency of 97% after 500 cycles. AlCl 3 /PC electrolyte with SG cathode exhibit a high specific capacity, stable cycling performance and rate capability. [ABSTRACT FROM AUTHOR]