Static Zn–Br2 batteries are considered an attractive option for cost-effective and high-capacity systems for large energy storage. Yet, the corrosive nature of the Zn–Br2 electrolytes entails a careful selection of all cells' ingredients to avoid rapid degradation of the batteries upon cycling. Thanks to their high chemical resistance and excellent conductivity, carbonaceous electrodes are typically utilized as current collectors for the cathode side, while thin Zn or Ti foils are most widely used as the anodes' current collectors. However, these metals tend to corrode fast, thus undermining the desirable performance of the cells as durable and stable rechargeable batteries. We demonstrate the effective utilization of carbon nanotubes (CNT) films as highly stable anode current collector for Zn–Br2 batteries. Dispersion of the CNT beforehand in slurries containing anionic, cationic, or neutral surfactants yielded distinct chemical and physical characteristics of these carbonaceous electrodes. This, in turn, led to significant differences in the morphology of the deposited Zn, consequently affecting the electrochemical performance of the Zn anodes. These findings provide insight into the interactions between Zn cations and the surface of CNTs, offering opportunities for further surface modifications of CNTs as effective anodes’ substrates for Zn–Br2 batteries.

The growing demand for energy has increased the need for battery storage, with lithium-ion batteries being widely used. Among those, nickel-rich layered lithium transition metal oxides [LiNi1-x-yCoxMnyO2 NCM (1 - x - y > 0.5)] are some of the promising cathode materials due to their high specific capacities and working voltages. In this study, we demonstrate that a thin, simple coating of polyalanine chiral molecules improves the performance of Ni-rich cathodes. The chiral organic coating of the active material enhances the discharge capacity and rate capability. Specifically, NCM811 and NCM622 electrodes coated with chiral molecules exhibit lower voltage hysteresis and better rate performance, with a capacity improvement of >10% at a 4 C discharge rate and an average improvement of 6%. We relate these results to the chirally induced spin selectivity effect that enables us to reduce the resistance of the electrode interface and to reduce dramatically the overpotential needed for the chemical process by aligning the electron spins.

Dry solid polymer electrolytes (SPEs), particularly those based on poly(ethylene oxide) (PEO), hold significant potential for advancing solid-state Li-metal battery (LMB) technology. Despite extensive research over the years, a comprehensive evaluation of Coulombic efficiency (CE), deposit stability, and cycle life for reversible Li metal electrodeposition in SPE-based cells is still lacking. In this study, we systematically assess the effect of cycling conditions on the CE of Li|SPE|Cu half cells and provide a thorough examination of different electrolyte chemistries, highlighting and explaining their performance across various parameters. While the efficiency of the PEO-based SPEs still falls short of the efficiency benchmark set by liquid and gel electrolytes, we demonstrated >95% CE with Lithium bis(fluorosulfonyl)imide (LiFSI)-based SPEs, surpassing previous reports for dry SPEs in a Li|SPE|Cu cells, this result marks a significant breakthrough. Furthermore, our findings highlight the critical impact of the Li-SPE interphase on these performance metrics. The LiFSI-based SPE forms a Li-rich, high-conductivity interphase, which not only enhances efficiency but also improves cycle life and Li deposit stability. These results underscore the importance of selecting the right polymer electrolyte chemistry and concentration to enhance SPE performance.

A critical current challenge in the development of all-solid-state lithium batteries (ASSLBs) is reducing the cost of fabrication without compromising the performance. Here we report a sulfide ASSLB based on a high-energy, Co-free LiNiO2 cathode with a robust outside-in structure. This promising cathode is enabled by the high-pressure O2 synthesis and subsequent atomic layer deposition of a unique ultrathin LixAlyZnzOδ protective layer comprising a LixAlyZnzOδ surface coating region and an Al and Zn near-surface doping region. This high-quality artificial interphase enhances the structural stability and interfacial dynamics of the cathode as it mitigates the contact loss and continuous side reactions at the cathode/solid electrolyte interface. As a result, our ASSLBs exhibit a high areal capacity (4.65 mAh cm−2), a high specific cathode capacity (203 mAh g−1), superior cycling stability (92% capacity retention after 200 cycles) and a good rate capability (93 mAh g−1 at 2C). This work also offers mechanistic insights into how to break through the limitation of using expensive cathodes (for example, Co-based) and coatings (for example, Nb-, Ta-, La- or Zr-based) while still achieving a high-energy ASSLB performance.

Magnesium-ion batteries (MIBs) are promising candidates for lithium-ion batteries because of their abundance, non-toxicity, and favorable electrochemical properties. This review explores the reaction mechanisms and electrochemical characteristics of Mg-alloy anode materials. While Mg metal anodes provide high volumetric capacity and dendrite-free electrodeposition, their practical application is hindered by challenges such as sluggish Mg²⁺ ion diffusion and electrolyte compatibility. Alloy-type anodes that incorporate groups XIII, XIV, and XV elements have the potential to overcome these limitations. We review various Mg alloys, emphasizing their alloying/dealloying reaction mechanisms, their theoretical capacities, and the practical aspects of MIBs. Furthermore, we discuss the influence of the electrolyte composition on the reversibility and efficiency of these alloy anodes. Emphasis is placed on overcoming current limitations through innovative materials and structural engineering. This review concludes with perspectives on future research directions aimed at enhancing the performance and commercial viability of Mg alloy anodes and contributing to the development of high-capacity, safe, and cost-effective energy storage systems.

The practical performance of Li-O2 batteries suffers from interfacial instabilities associated with the reaction intermediates. These instabilities on the cathode-electrolyte interface dictate the direction of the oxygen evolution and reduction reactions (OER/ORR) in Li-O2 batteries. Despite intensive research on chemical instabilities in the reaction intermediates, there is limited work on understanding the importance of stress on the interfacial dynamics. To address this gap, in-situ curvature measurements were conducted to probe interfacial stress generation during electrochemical polarization on Au cathode in DMSO electrolytes. Charge accumulation induces tensile stress, whereas compressive stress generation is associated with the adsorbate-induced stress and mismatch strain between reaction intermediates and the Au surface. Abrupt stress relaxation on the onset of discharge presents evidence for a contribution of electrostriction stress. Adsorption of redox mediator nitrate ions induces compressive stress before ORR. Unique findings demonstrate the impact of interfacial stress on the OER/ORR in Li-O2 batteries.

Several decades after the invention of the flow Zn-Br2 systems, persistent attempts have been made to develop stationary Zn-Br2 batteries. Such development should increase the energy density of the system simultaneously significantly reducing their cost and opening new challenges associated with the cell design and its performance. One of the major concerns is the rapid self-discharge of stationary systems leading to spontaneous charge loss during battery storage time. While self-discharge in flow cells is generally attributed to the chemical oxidation of the Zn anode, we show that the origin of self-discharge in a static configuration is completely different. By systematic investigations of activated carbon with different surface areas under varied charging conditions, mechanistic insights into this phenomenon were provided. Based on this understanding, we proposed herein an effective way to suppress the cathode's self-discharge by encapsulation of a bromine complexing agent inside the electrode's pore matrix. The modified electrodes unveil unique chemical kinetics of deaggregation of the stable fuse salt phase composed of bromine complexing agent and Br3− anions upon discharging. To the best of our knowledge, such a phenomenon has not been reported yet. The proposed system demonstrates high capacity (up to 300 mAh/g) and impressive long-term stability.

MnO2-based zinc-ion batteries have emerged as a promising candidate for next-generation energy storage systems. Despite extensive research on MnO2 electrodes, the charging mechanism in mildly acidic electrolytes remains debated. Most studies have focused on α-MnO2, and this study aims to shed light on the identity of the charge carrier in β-MnO2 and the role of the Mn2+ cations. By employing in situ EQCM-D measurements, along with ssNMR, XRD, TEM, and in situ pH monitoring, we demonstrated that the charging mechanism is primarily governed by proton de/intercalation. Compared to α-MnO2, with its larger 2 × 2 tunnels that accommodate hydronium ions, the β-phase has smaller 1 × 1 tunnels, permitting only the insertion of bare protons. During cycling, we observed the formation of new phases on β-MnO2 originating from the repetitive electrodeposition/dissolution of Mn2+. In addition, these phases can reversibly host hydronium ions, resulting in a mixed charging mechanism that involves the insertion of both H3O+ and H+.

Rechargeable manganese batteries hold promise for large-scale energy storage due to the abundance and eco-friendly nature of manganese. A key challenge is developing cathode materials capable of reversibly inserting Mn ions with a high specific capacity. Here, we demonstrate that perylene-3,4,9,10-tetracarboxylic dianhydride electrodes efficiently and reversibly insert Mn2+ ions in 3 M MnCl2 aqueous electrolyte solutions. Leveraging the carbonyl groups and the π-electron configuration, such compounds can serve as robust redox centers, facilitating reversible interactions with divalent ions such as Mn2+. Through comprehensive studies involving electrochemistry, elemental analyses, spectroscopy, and structural analysis, we explored these systems and found them as promising anode materials for Mn batteries. Demonstrating excellent Mn storage capabilities, such molecules could attain a reversible capacity of approximately >185 mAh g-1 at a current density of 100 mA g-1, maintaining an average voltage of approximately 0.8 V vs Mn/Mn2+, while exhibiting notable capacity retention.