Reversible, Dendrite-Free, High-Capacity Aluminum Metal Anode Enabled by Aluminophilic Interface Layer

MXene-Based Mixed Conductor Interphase for Dendrite-Free Flexible Al Organic Battery

Al batteries are promising post-Li battery technologies for large-scale energy storage applications owing to their low cost and high theoretical capacity. However, one of the challenges that hinder their development is the unsatisfactory plating/stripping of the Al metal anode. To circumvent this issue, an ultrathin MXene layer is constructed on the surface of Al by in situ chemical reactions at room temperature. The as-prepared flexible MXene film acts like armor to protect the Al-metal by its high ionic conductivity and high mechanical flexibility. The MXene endow the Al anode with a long cyclic life of more than 5000 h at ultrahigh current density of 50 mA cm-2 for Al//Al batteries and a retention of 100% over 200 cycles for 355 Wh kg-1 PTO//Al batteries. This work provides fresh insights into the formation and regulation of stable electrode-electrolyte interfaces as well as effective strategies for improving Al metal batteries.

Stable Aluminum Metal Anode Enabled by Dual-Functional Molybdenum Nanoparticles

Constructing robust anode with strong aluminophilicity and rapid desolvation kinetics is essential for achieving high utilization, long-term durability, and superior rate performance in Al metal-based energy storage, yet remains largely unexplored. Herein, molybdenum nanoparticles embedded onto nitrogen-doped graphene (Mo@NG) are designed and prepared as Al host to regulate the deposition behavior and achieve homogeneous Al plating/stripping. The monodispersed Mo nanoparticles reduce the desolvation energy barrier and promote the deposition kinetics of Al. Additionally, Mo nanoparticles act as aluminophilic nucleation sites to minimize the Al nucleation overpotential, further guiding uniform and dense Al deposition. As a result, the dual-functional Mo@NG endows Al anodes with low voltage hysteresis, reversible Al plating/stripping with high coulombic efficiency, and excellent high-rate capability under 5 mA cm-2 . Moreover, the as-designed Al metal full batteries deliver a high capacity retention of 92.8% after 3000 cycles at 1 A g-1 . This work provides an effective solution to optimize the electrochemical properties of Al metal anode from the perspective of desolvation and deposition reactions, towards the development of high-safety and long-cycling aluminum-ion batteries.

Solvation Sheath Engineering by Multivalent Cations Enabling Multifunctional SEI for Fast-Charging Lithium-Metal Batteries

With the pursuit of high energy and power density, the fast-charging capability of lithium-metal batteries has progressively been the primary focus of attention. To prevent the formation of lithium dendrites during fast charging, the ideal solid electrolyte interphase should be capable of concurrent fast Li+ transport and uniform nucleation sites; however, its construction in a facile manner remains a challenge. Here, as Al3+ has a higher charge and Al metal is lithiophilic, we tuned the Li+ solvation structure by introducing LiNO3 and aluminum ethoxide together, resulting in the dissolution of LiNO3 and the simultaneous generation of fast ionic conductor and lithiophilic sites. Consequently, our approach facilitated the deposition of lithium metal in a uniform and chunky way, even at a high current density. As a result, the Coulombic efficiency of the Li||Cu cell increased to over 99%. Moreover, the Li||LiFePO4 full cell demonstrated significantly enhanced cycling performance with a remarkable capacity retention of 94.5% at 4 C, far superior to the 46.1% capacity retention observed with the base electrolyte.

Rechargeable Hydrogen-Chlorine Battery Operates in a Wide Temperature Range

Hydrogen-chlorine (H2-Cl2) fuel cells have distinct merits due to fast electrochemical kinetics but are afflicted by high cost, low efficiency, and poor reversibility. The development of a rechargeable H2-Cl2 battery is highly desirable yet challenging. Here, we report a rechargeable H2-Cl2 battery operating statically in a wide temperature ranging from -70 to 40 °C, which is enabled by a reversible Cl2/Cl- redox cathode and an electrocatalytic H2 anode. A hierarchically porous carbon cathode is designed to achieve effective Cl2 gas confinement and activate the discharge plateau of Cl2/Cl- redox at room temperature, with a discharge plateau at ∼1.15 V and steady cycling for over 500 cycles without capacity decay. Furthermore, the battery operation at an ultralow temperature is successfully achieved in a phosphoric acid-based antifreezing electrolyte, with a reversible discharge capacity of 282 mAh g-1 provided by the highly porous carbon at -70 °C and an average Coulombic efficiency of 91% for more than 300 cycles at -40 °C. This work offers a new strategy to enhance the reversibility of aqueous chlorine batteries for energy storage applications in a wide temperature range.

Balancing Interfacial Reactions through Regulating p-Band Centers by an Indium Tin Oxide Protective Layer for Stable Zn Metal Anodes

Metallic zinc (Zn) is considered as one of the most attractive anode materials for the post-lithium metal battery systems owing to the high theoretical capacity, low cost, and intrinsic safety. However, the Zn dendrites and parasitic side reaction impede its application. Herein, we propose a new principle of regulating p-band center of metal oxide protective coating to balance Zn adsorption energy and migration energy barrier for effective Zn deposition and stripping. Experimental results and theoretical calculations indicate that benefiting from the uniform zincophilic nucleation sites and fast Zn transport on indium tin oxide (ITO), highly stable and reversible Zn anode can be achieved. As a result, the I-Zn symmetrical cell achieves highly reversible Zn deposition/stripping with an extremely low overpotential of 9 mV and a superior lifespan over 4000 h. The Cu/I-Zn asymmetrical cell exhibits a long lifetime of over 4000 cycles with high average coulombic efficiency of 99.9 %. Furthermore, the assembled I-Zn/AC full cell exhibits an excellent lifetime for 70000 cycles with nearly 100 % capacity retention. This work provides a general strategy and new insight for the construction of efficient Zn anode protection layer.

Anions Regulation Engineering Enables a Highly Reversible and Dendrite-Free Nickel-Metal Anode with Ultrahigh Capacities

The development of safe and high-energy metal anodes represents a crucial research direction. Here, the achievement of highly reversible, dendrite-free transition metal anodes with ultrahigh capacities by regulating aqueous electrolytes is reported. Using nickel (Ni) as a model, theoretical and experimental evidence demonstrating the beneficial role of chloride ions in inhibiting and disrupting the nickel hydroxide passivation layer on the Ni electrode is provided. As a result, Ni anodes with an ultrahigh areal capacity of 1000 mAh cm-2 (volumetric capacity of ≈6000 mAh cm-3 ), and a Coulombic efficiency of 99.4% on a carbon substrate, surpassing the state-of-the-art metal electrodes by approximately two orders of magnitude, are realized. Furthermore, as a proof-of-concept, a series of full cells based on the Ni anode is developed. The designed Ni-MnO2 full battery exhibits a long lifespan of 2000 cycles, while the Ni-PbO2 full battery achieves a high areal capacity of 200 mAh cm-2 . The findings of this study are important for enlightening a new arena toward the advancement of dendrite-free Ni-metal anodes with ultrahigh capacities and long cycle life for various energy-storage devices.