The degradation or dendrite formation of zinc metal electrodes has shown to limit the cycle life of rechargeable aqueous zinc batteries, and a few anode protection methods are proposed. We herein demonstrate that, except for external protections, a simple design of an electrolyte can effectively promote stable and facile Zn stripping/plating from/on zinc electrodes. By using Zn­(ClO4)2 in the aqueous electrolyte, reversible Zn stripping/plating is achieved for over 3000 h at 1 mA cm–2 current density and 1 mA h cm–2 capacity, superior to the conventional ZnSO4 electrolyte. The overpotential is constant within each cycle and only increases slightly with the increase of current densities. The excellent performance is guaranteed by the controlled formation of a Cl– containing layer, which limits continuous side reactions. The Zn­(ClO4)2 electrolyte shows anodic stability up to 2.4 V, and excellent electrochemical performance is achieved for an example cell with the VO2 cathode, confirming the applicability of the electrolyte for Zn batteries.

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M = Co, Ni) can deliver a theoretical specific capacity exceeding 300 mAh g −1 by unlocking the anionic redox chemistry. [2] However, LRMOs are plagued by issues of low Coulombic efficiency, capacity/voltage decay and voltage hysteresis mainly due to irreversible oxygen loss and transition metal (TM) migration. [3] Oxygen loss is proposed to lower the migration barrier of transition metals, induce the formation of cracks, accelerate electrolyte decomposition, and further impose thermal runway risk. [4] Many approaches, such as composition tailoring, [5] element doping, [6] gradient concentration design [7] and surface coating, [8] have been established to stabilize LRMOs. Among them, surface coating is most straightforward to mitigate oxygen loss on charging LRMOs.For practical electrode fabrication, cathode materials are usually prepared in microspheres composed of nanosized primary particles to achieve high tap density and facilitate slurry preparation and casting on current collector. Most reported coating techniques, for example, ball milling, atomic layer deposition and wet chemistry method involving coprecipitation and calcination, often build a protective layer on the secondary particles due to weak interaction between inner primary particles and coating material. Few researches have realized effective coating on primary particles of cathode materials. [9] For example, atomic layer deposition and high temperature annealing was employed to melt coated Li 3 PO 4 layer into grain boundaries of LiNi 0.76 Mn 0.14 Co 0.10 O 2 . [9b] Besides, a conformal poly(3,4-ethylenedioxythiophene) layer was generated on both secondary and primary particles of LiNi 0.85 Co 0.10 Mn 0.05 O 2 and Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 by oxidative chemical vapor deposition. [9c] Recently, a reactive boride infusion strategy was adopted to coat Co x B on primary particles of LiNi 0.8 Co 0.1 Mn 0.1 O 2 at room temperature. [9d] However, these primary particle coating strategies are often plagued by high cost and/or complicated procedures. It is desirable to develop facile, scalable routes for surface modification of primary particles to improve the performance of LRMO cathode materials.In this study, we proposed a simple yet efficient strategy for homogenously coating Li 2 TiO 3 (LTO) on the primary particles of Li 1.08 Mn 0.54 Co 0.13 Ni 0.13 O 2 (LRMO). As a lithium-ion conducting material, LTO not only exhibits chemical and Li-rich Mn-based oxides (LRMOs) are promising cathode materials for next-generation lithium-ion batteries (LIBs) with high specific energy (≈900 Wh kg −1 ) because of anionic redox contribution. However, LRMOs suffer from issues such as irreversible release of lattice oxygen, transition metal (TM) dissolution, and parasitic cathode-electrolyte reactions. Herein, a facile, scalable route to build homogenous and ultrathin Li 2 TiO 3 (LTO) coating layer on the primary particles of LRMO through molten salt (LiCl) assisted solid-liquid reaction between TiO 2 and Li 1.08 Mn 0.54 Co 0.13 Ni 0.13 O 2 is repo...

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Building stable, efficient, and low-cost oxygen evolution electrodes is of paramount importance but challenging for practical water electrolysis. Here, we report a robust electrode at high current densities (>1 A cm–2) by interfacial engineering of coupled phase segregation and refusion with the rational electrodepositing order of a single-crystalline Ni3S2 outer layer and the polycrystalline Fe­(OH)2 inner layer. The Ni3S2 layer blocks the Fe dissolution–redeposition process at the electrode/electrolyte interface but favors the dynamic Fe segregation and refusion at the Ni3S2/Fe­(OH)2 interface to form new NiFeO x H y S z species, enhancing catalyst durability and activity. The study highlights that the rational modulating phase segregation and refusion process at the electroactive interface is a facile, effective strategy to enhance the activity and durability of electrocatalysts that experience a phase transition under operating conditions.

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