Ultrarapid Nanomanufacturing of High-Quality Bimetallic Anode Library toward Stable Potassium-Ion Storage.

Bimetallic alloy nanomaterials are promising anode materials for potassium-ion batteries (KIBs) due to their high electrochemical performance. The most well-adopted fabrication method for bimetallic alloy nanomaterials is tube furnace annealing (TFA) synthesis, which can hardly satisfy the trade-off among granularity, dispersity and grain coarsening due to mutual constraints. Herein, we report a facile, scalable and ultrafast high-temperature radiation (HTR) method for the fabrication of a library of ultrafine bimetallic alloys with narrow size distribution (≈10-20 nm), uniform dispersion and high loading. The metal-anchor containing heteroatoms (i.e., O and N), ultrarapid heating/cooling rate (≈103  K s-1 ) and super-short heating duration (several seconds) synergistically contribute to the successful synthesis of small-sized alloy anodes. As a proof-of-concept demonstration, the as-prepared BiSb-HTR anode shows ultrahigh stability indicated by negligible degradation after 800 cycles. The in situ X-ray diffraction reveals the K+ storage mechanism of BiSb-HTR. This study can shed light on the new, rapid and scalable nanomanufacturing of high-quality bimetallic alloys toward extended applications of energy storage, energy conversion and electrocatalysis.

A Novel Hierarchical Structure of SnCu2Se4/d-Ti3C2Tx/NPC for a Lithium/Sodium Ion Battery and Hybrid Capacitor with Long-Term Cycling Stabilities.

To alleviate kinetics imbalance and capacity insufficiency simultaneously, a novel hierarchical structure (SnCu2Se4/d-Ti3C2Tx/NPC) composed of delaminated Ti3C2Tx, SnCu2Se4 nanoparticles, and N-doped porous carbon layers is designed as a battery-type anode for lithium/sodium ion hybrid capacitor (LIC/SIC). The combination of SnCu2Se4 nanoparticles with high specific capacity, d-Ti3C2Tx with accelerated ion diffusion path, and NPC with enhanced electronic conductivity makes the SnCu2Se4/d-Ti3C2Tx/NPC composite possess excellent cycling stabilities in half-cell lithium-ion and sodium-ion batteries (LIB and SIB), with capacities of 114 mAh g-1 after 6000 cycles at 10 A g-1 for LIB and 296 mAh g-1 after 900 cycles at 1.0 A g-1 for SIB. The rate performance is also outstanding, with recovered capacity of 738 mAh g-1 at 0.1 A g-1 after cycles at current densities up to 50 A g-1 for LIB. Subsequently, LIC and SIC based on the SnCu2Se4/d-Ti3C2Tx/NPC anode and activated carbon cathode exhibit high energy densities of 147.9 and 158.6 Wh kg-1 at a power density of 100 W kg-1, respectively. They also possess distinctive long lifespans with capacity retentions of 78 and 81% after 10,000 cycles at 1.0 A g-1, respectively, demonstrating the feasibility of SnCu2Se4/d-Ti3C2Tx/NPC toward energy devices requiring high energy density, power density, and long-term stability.

Ultrafast Porous Carbon Activation Promises High-Energy Density Supercapacitors.

Activated porous carbons (APCs) are traditionally produced by heat treatment and KOH activation, where the production time can be as long as 2 h, and the produced activated porous carbons suffer from relatively low specific surface area and porosity. In this study, the fast high-temperature shock (HTS) carbonization and HTS-KOH activation method to synthesize activated porous carbons with high specific surface area of ≈843 m2 g-1 , is proposed. During the HTS process, the instant Joule heating (at a heating speed of ≈1100 K s-1 ) with high temperature and rapid quenching can effectively produce abundant pores with homogeneous size-distribution due to the instant melt of KOH into small droplets, which facilitates the interaction between carbon and KOH to form controllable, dense, and small pores. The as-prepared HTS-APC-based supercapacitors deliver a high energy density of 25 Wh kg-1 at a power density of 582 W kg-1 in the EMIMBF4 ionic liquid. It is believed that the proposed HTS technique has created a new pathway for manufacturing activated porous carbons with largely enhanced energy density of supercapacitors, which can inspire the development of energy storage materials.

A stable and ultrafast K ion storage anode based on phase-engineered MoSe2.

Potassium-ion batteries (PIBs) are attracting increasing attention due to the abundance of K resources, but the sluggish kinetics and inferior cycling stability of anodes still hinder their application. Herein, we present a hybrid 1T/2H phase MoSe2 anode, which shows noticeable pseudocapacitive response and fast kinetics for K storage. Correspondingly, superior electrochemical performances including a high reversible capacity of 440 mA h g-1 after 100 cycles at 0.1 A g-1 and superb rate capacity of 211 mA h g-1 at 20.0 A g-1 are achieved. We believe this work may shed light on the phase engineering of transition metal compounds for rapid charging PIBs.

Large Interlayer Spacing of Few-Layered Cobalt-Tin-Based Sulfide Providing Superior Sodium Storage.

Mixed transition metal sulfides (MTMSs) have been regarded as a potential anode material for sodium-ion batteries (SIBs) due to their high reversible specific capacity. Herein, nanoflower-like few-layered cobalt-tin-based sulfide (F-CoSnS) with a large interlayer spacing is synthesized via a facile route for superior sodium storage. The growth mechanism of this unique F-CoSnS is systematically studied. Such distinctive nanostructured engineering synergistically combines a broad interlayer spacing (∼ 0.85 nm), the functionalities of few (2-3) layers, and the introduction of heterogeneous metal atoms, reducing the ion diffusion energy barrier for high-efficiency intercalation/deintercalation of Na+ ions, as revealed by density functional theory (DFT) calculations. With further incorporation of a three-dimensional (3D) conductive network, the F-CoSnS@C electrode shows a large sodium storage capacity (493.4 mAh g-1 at 50 mA g-1), remarkable rate capability (316.1 mAh g-1 at 1600 mA g-1), and superior cycling stability (450 mAh g-1 at 50 mA g-1 with 91.2% capacity retention, 0.044% fading rate per cycle, and approximately 100% Coulombic efficiency after 200 cycles). This work demonstrates that the few-layered ternary MTMSs are highly applicable for the development of advanced SIB anode materials with high performance.

Nanomanufacturing of RGO-CNT Hybrid Film for Flexible Aqueous Al-Ion Batteries.

A highly electrically conductive film-type current collector is an essential part of batteries. Apart from the metal-based current collectors, lightweight and highly conductive carbon materials such as reduced graphene oxide (RGO) and carbon nanotubes (CNTs) show great potential as current collectors. However, traditional RGO manufacturing usually requires a long time and high energy, which decreases the product yielding rate and manufacturing efficiency. Moreover, the performance of the manufactured RGO needs to be further improved. In this work, CNT and GO are evenly mixed into GO-CNT, which can be directly reduced into RGO-CNT by Joule heating at 2936 K within less than 1 min. The fabricated RGO-CNT achieves a high electrical conductivity of 2750 S cm-1 , and realizes a 106 -fold increase. The assembled flexible aqueous Al-ion battery with RGO-CNT as the current collector exhibits impressive electrochemical performance in terms of superior cycling stability and exceptional rate capability, and excellent mechanical ability regarding the tolerance to mechanical damage such as bending, folding, piercing, and cutting without detrimental consequences.

Mesoporous ZnCo2O4/rGO nanocomposites enhancing sodium storage.

In this study, mesoporous ZnCo2O4/rGO nanocomposites were favorably synthesized via a simple solvothermal technique. As a prospective anode material for sodium-ion batteries, the resulting ZnCo2O4/rGO-II nanocomposite exhibited superior electrochemical sodium storage performance with predominant specific capacity, favorable cyclability and ascendant rate capability. For example, an outstanding discharge capacity of 210.5 mAh g-1 was delivered at a current density of 200 mA g-1. Notably, the nanocomposite could yield a discharge capacity of 101.7 mAh g-1 at a current density of 1000 mA g-1 after 500 loops, which certifies its superior capacity retention and predominant cycling stability. The boosted performance of the anode materials is due to the mutual synergistic effect resulting from a combination of the mesoporous ZnCo2O4 nanospheres and conducting reduced graphene oxide nanosheets.

Preparation and Capacity-Fading Investigation of Polymer-Derived Silicon Carbonitride Anode for Lithium-Ion Battery.

Polymer-derived silicon carbonitride (SiCN) materials have been synthesized via pyrolyzing from five poly(silylcarbondiimide)s with different contents of carbon (labeled as 1-5#). The morphological and structural measurements show that the SiCN materials are mixtures of nanocrystals of SiC, Si3N4, and graphite. The SiCN materials have been used as anodes for lithium-ion batteries. Among the five polymer-derived SiCN materials, 5#SiCN, derived from dichloromethylvinylsilane and di-n-octyldichlorosilane, has the best cycle stability and a high-rate performance at the low cutoff voltage of 0.01-1.0 V. In lithium-ion half-cells, the specific delithiation capacity of 5#SiCN anode still remains at 826.7 mA h g-1 after 100 charge/discharge cycles; it can even deliver the capacity above 550 mA h g-1 at high current densities of 1.6 and 2 A g-1. In lithium-ion full cells, 5#SiCN anode works well with LiNi0.6Co0.2Mn0.2O2 commercial cathode. The outstanding electrochemical performance of 5#SiCN anode is attributed to two factors: (1) the formation of a stable and compact solid electrolyte interface layer on the anode surface anode, which protects the electrode from cracking during the charge/discharge cycle; and (2) a large amount of carbon component and the less Si3N4 phase in the 5#SiCN structure, which provides an electrochemical reactive and conductive environment in the SiCN structure, benefit the lithiation/delithiation process. In addition, we explore the reason for the capacity fading of these SiCN anodes.