Constructing Highly Stable Zinc Metal Anodes via Induced Zn(002) Growth.

The nonuniform electric field at the surface of a zinc (Zn) anode, coupled with water-induced parasitic reactions, exacerbates the growth of Zn dendrites, presenting a significant impediment to large-scale energy storage in aqueous Zn-ion batteries. One of the most convenient strategies for mitigating dendrite-related issues involves controlling crystal growth through electrolyte additives. Herein, we present thiamine hydrochloride (THC) as an electrolyte additive capable of effectively stabilizing the preferential deposition of the Zn(002) plane. First-principles calculations reveal that THC tends to adsorb on Zn(100) and Zn(101) planes and is capable of inducing the deposition of Zn ion onto the (002) plane and the preferential growth of the (002) plane, resulting in a flat and compact deposition layer. A THC additive not only effectively suppresses dendrite growth but also prevents the generation of side reactions and hydrogen evolution reaction. Consequently, the Zn||Zn symmetric battery exhibits long-term cycling stability of over 3000 h at 1 mA cm-2/1 mAh cm-2 and 1000 h at 10 mA cm-2/10 mAh cm-2. Furthermore, the NH4V4O10||Zn full battery also displays excellent cycling stability and a high reversible capacity of 210 mAh g-1 after 1000 cycles at 1 A g-1, highlighting a significant potential for practical applications.

In situ fluoro-oxygen codoped graphene layer for high-performance lithium metal anode.

Because traditional lithium-ion batteries have been unable to meet the energy density requirements of various emerging fields, lithium-metal batteries (LMBs), known for their high energy density, are considered promising next-generation energy storage batteries. However, a series of problems, including low coulombic efficiency and low safety caused by dendrites, limit the application of lithium metal batteries. Herein, fluoro-oxygen codoped graphene (FGO) was used to modify the copper current collector (FGO@Cu). FGO-coated current collector provides more even nucleation sites to reduce the local effective current density. FGO is partly reduced during cycling and helps form stable LiF-rich SEI. Moreover, graphene's oxygen and fluorine functional groups reconstruct the current density distribution, promoting uniform lithium plating. The FGO@Cu current collector demonstrates superior properties than commercial Cu foil. The FGO@Cu delivers a 97% high CE for over 250 cycles at 1 mA cm-2. The FGO@Cu symmetrical battery cycled at 1 mA cm-2 for over 650 h. LiFePO4 fuel cell with a lithium-plated FGO@Cu collector as an anode exhibits superior cycling stability.

Stabilizing a Li1.3Al0.3Ti1.7(PO4)3/Li metal anode interface in solid-state batteries with a LiF/Cu-rich multifunctional interlayer.

Li1.3Al0.3Ti1.7(PO4)3 (LATP) has attracted much attention due to its high ionic conductivity, good air stability and low cost. However, the practical application of LATP in all-solid-state lithium batteries faces serious challenges, such as high incompatibility with lithium metal and high interfacial impedance. Herein, a CuF2 composite layer was constructed at a Li/LATP interface by a simple drop coating method. CuF2 in the interlayer reacts with lithium metal in situ to form a multifunctional interface rich in Cu and LiF. The multifunctional layer not only brings about close interfacial contact between LATP and Li metal, but also effectively prevents the electrochemical reaction of LATP with Li metal, and suppresses the electron tunneling and dendrite growth at the interface. The interfacial resistance of Li/CuF2@LATP/Li symmetric batteries is significantly reduced from 562 to 92 Ω, and the critical current density is increased to 1.7 mA cm-2. An impressive stable cycle performance of over 6000 h at 0.1 mA cm-2/0.1 mA h cm-2, 2200 h at 0.2 mA cm-2/0.2 mA h cm-2 and 1600 h at 0.3 mA cm-2/0.3 mA h cm-2 is achieved. Full batteries of LiFePO4/CuF2@LATP/Li also show a high capacity retention ratio of 80.3% after 540 cycles at 25 °C. This work provides an effective and simple composite layer solution to address the interfacial problem of Li/LATP.

Simultaneously Tailoring Zinc Deposition and Solvation Structure by Electrolyte Additive.

Aqueous zinc ion batteries (AZIBs) have attracted intense attention due to their high safety and low cost. Unfortunately, the serious dendrite growth and side reactions of the Zn metal anode in an aqueous electrolyte result in rapid battery failure, hindering the practical application of AZIBs. Herein, sodium gluconate as a dual-functional electrolyte additive has been employed to enhance the electrochemical performance of AZIBs. Gluconate anions preferentially adsorb on the surface of the Zn anode, which effectively prevents H2 evolution and induces uniform Zn deposition to suppress dendrite growth. Moreover, the gluconate anions can highly coordinate with Zn2+, promoting the dissolution of [Zn(H2O)6]2+ to inhibit side reactions and the water-induced corrosion reaction. As a result, the Zn||Zn symmetric battery exhibits a long-term cycling stability of over 3000 h at 1 mA cm-2/1 mA h cm-2 and 600 h at 10 mA cm-2/10 mA h cm-2. Furthermore, the NH4V4O10||Zn full battery also displays excellent cycling stability and a high reversible capacity of 193 mA h g-1 at 2 A g-1 after 1000 cycles. Given the low-cost advantage of SG, the proposed interface chemistry modulation strategy holds considerable potential for promoting the commercialization of AZIBs.

Inorganic Hybrid Interfacial Layer for a Stable Zinc Metal Anode.

In aqueous zinc-ion batteries (AZIBs), the zinc metal anode faces serious problems such as dendrite growth, interface corrosion, and byproduct accumulation, which hinder the commercialization process of AZIBs. Herein, an inorganic hybrid interfacial layer ZnF2/ZnSe (ZnFS) including the insulating interfacial phase (ZnF2) and conductive interfacial phase (ZnSe) has been manufactured. ZnF2 provides excellent corrosion resistance, inhibiting the corrosion and passivation of the zinc metal anode to enhance interfacial stability. The conductive ZnSe can reduce the interfacial resistance and induce the rapid migration of Zn2+, leading to the uniform deposition of Zn to inhibit the dendrite growth. Consequently, the Zn/ZnFS//Zn/ZnFS symmetrical batteries can run stably for more than 2200 h at 1 mA cm-2/1 mAh cm-2 and over 700 h at 5 mA cm-2/5 mAh cm-2. At the same time, the average Coulombic efficiency of the Zn/ZnFS//Ti half batteries reaches 98.3% after 600 cycles (1 mA cm-2/1 h), indicating that the reversibility of zinc was greatly improved. The full batteries based on the Zn/ZnFS anode and (NH4)2V10O25·8H2O cathode perform a high capacity ratio of 73.4% after 620 cycles at 1 A g-1. The concept of hybrid interface layer design can provide inspiration for the modification of metal anode.

Confining ZnS/SnS2 Ultrathin Heterostructured Nanosheets in Hollow N-Doped Carbon Nanocubes as Novel Sulfur Host for Advanced Li-S Batteries.

Hollow nanostructured hosts are important scaffolds to achieve high sulfur loading, fast charge transfer, and conspicuous restraint of lithium polysulfides (LiPSs) shuttling in lithium-sulfur (Li-S) batteries. However, developing high-efficiency hollow hosts for improving utilization and conversion of aggregated sulfur in the hollow chamber remains a longstanding challenge. Herein, hollow N-doped carbon nanocubes confined petal-like ZnS/SnS2 heterostructures (ZnS/SnS2 @NC) as a conceptually novel host for Li-S batteries are reported. Specifically, compared to consubstantial hollow double-shelled hosts, the ZnS/SnS2 @NC with higher effective active surface area brings dense contact with sulfur and enhances efficient adsorption sites for binding LiPSs and accelerating their conversion. Benefiting from the unique structure and sophisticated composition, the resulting S@ZnS/SnS2 @NC cathodes exhibit 1294 mAh g-1 at 0.2 C, an ultralow capacity decay of 0.016% per cycle over 500 cycles at 1.0 C, and a high area capacity of 4.77 mAh cm-2 at 0.5 C (5.9 mg cm-2 ). Meanwhile, the performance evolution of S@ZnS/SnS2 @NC cathodes under various sulfur loadings is further investigated by using EIS, which provides the beneficial guidance to explore viable strategies further optimizing their performance. This work sheds new insights into the design of hollow nanostructured hosts with a distinguished ability to regulate LiPSs in Li-S batteries.

Conversion of MoS2 to a Ternary MoS2- xSe x Alloy for High-Performance Sodium-Ion Batteries.

MoS2 has attracted tremendous attention as an anode for Na-ion batteries (NIBs) owing to its high specific capacity and layered graphite-like structure. Herein, MoS2 is converted to a ternary MoS2- xSe x alloy through the selenizing process in order to boost the electrochemical performance for Na-ion batteries. Conversion of MoS2 to MoS2- xSe x expands interlayer spacing, improves electronic conductivity, and creates more defects. The expanded interlayer spacing decreases Na+ diffusion resistance and facilitates Na+ fast transfer. The integrated graphene as a conductive network offers effective pathway for electron migration and maintains structural stability of electrodes during cycles. The ternary MoS1.2Se0.8/graphene (MoS1.2Se0.8/G) electrode demonstrates an extremely high reversible capacity of 509 mA h g-1 after 200 cycles at 0.1 A g-1 (capacity retention of 109%) as an anode for sodium-ion batteries. Even at 2 A g-1 and after 700 cycles, the MoS1.2Se0.8/G electrode also displays a relatively high reversible capacity of 178 mA h g-1. Full cells assembled with Na3V2(PO4)2F3 cathodes and MoS1.2Se0.8/G anodes reveal high charge/discharge capacities. This work demonstrates that the ternary MoS2- xSe x alloy could be a potential anode material for Na-ion storage.

Achieving a High-Performance Carbon Anode through the P-O Bond for Lithium-Ion Batteries.

Carbon materials with high initial Coulombic efficiency (ICE) and specific capacity in lithium-ion batteries are highly attractive. Herein, P-doped carbon has been prepared, and as an anode for lithium-ion batteries, it exhibits remarkably improved ICE and reversible capacity. P atoms are apt for the formation of the P-O bond in carbon with oxygen-containing groups. The doped P content strongly depends on the O content in carbon. The high-doped P content of 5.79 at. % can be obtained through changing the O content in carbon. Carbon with high contents of P and O displays high ICE and capacity as an anode for lithium-ion batteries. The P-O bond in carbon changes the morphology and composition of the solid electrolyte interface (SEI) layer and is beneficial to the formation of a thin and dense SEI layer. The P-O bond in carbon prevents the permeation and decomposition of solvated PF6- in the interior of the electrode during cycling, resulting in the improved ICE, reversible capacity, and rate capability. As an anode for lithium-ion batteries, the ICE can be improved to 70.9% for carbon with the P-O bond from 36.9% for carbon without the P-O bond. Carbon with the P-O bond displays high specific capacities of 566 mA h g-1 after 100 cycles at 0.1 A g-1 and 432 mA h g-1 after 1000 cycles at 1 A g-1. This design offers a simple and efficient method to improve the ICE and reversible capacity of hard carbon.

Vertically Oxygen-Incorporated MoS2 Nanosheets Coated on Carbon Fibers for Sodium-Ion Batteries.

Developing a high-performance anode with high reversible capacity, rate performance, and great cycling stability is highly important for sodium-ion batteries (SIBs). MoS2 has attracted extensive interest as the anode for SIBs. Herein, the vertically oxygen-incorporated MoS2 nanosheets/carbon fibers are constructed via a facile hydrothermal method and then by simple calcination in air. Oxygen incorporation into MoS2 can increase the defect degree and expand the interlayer spacing. Vertical MoS2 nanosheet array coated on carbon fibers not only can expose rich active sites and reduce the diffusion distance of Na+, but also improve the electronic conductivity and enhance structural stability. Meanwhile, interlayer-expanded MoS2 can decrease Na+ diffusion resistance and increase accessible active sites for Na+. In this work, the electrode combining the oxygen-incorporated strategy with vertical MoS2 nanosheet-integrated carbon fibers displays high specific capacities of 330 mAh g-1 over 100 cycles at a current density of 0.1 A g-1 together with excellent rate behavior as the anode for SIBs. This strategy offers a helpful way for improving the electrochemical performance.

Hollow core-shell structured Si/C nanocomposites as high-performance anode materials for lithium-ion batteries.

Hollow core-shell structured Si/C nanocomposites were prepared to adapt for the large volume change during a charge-discharge process. The Si nanoparticles were coated with a SiO2 layer and then a carbon layer, followed by etching the interface SiO2 layer with HF to obtain hollow core-shell structured Si/C nanocomposites. The Si nanoparticles are well encapsulated in a carbon matrix with an internal void space between the Si core and the carbon shell. The hollow core-shell structured Si/C nanocomposites demonstrate a high specific capacity and excellent cycling stability, with capacity decay as small as 0.02% per cycle. The enhanced electrochemical performance can be attributed to the fact that the internal void space can accommodate the volume expansion of Si during lithiation, thus preserving the structural integrity of electrode materials, and the carbon shell can increase the electronic conductivity of the electrode.