A Room-Temperature Self-Healing Liquid Metal-Infilled Microcapsule Driven by Coaxial Flow Focusing for High-Performance Lithium-Ion Battery Anode

Liquid metals have attracted a lot of attention as self-healing materials in many fields. However, their applications in secondary batteries are challenged by electrode failure and side reactions due to the drastic volume changes during the "liquid-solid-liquid" transition. Herein, a simple encapsulated, mass-producible method is developed to prepare room-temperature liquid metal-infilled microcapsules (LMMs) with highly conductive carbon shells as anodes for lithium-ion batteries. Due to the reasonably designed voids in the microcapsule, the liquid metal particles (LMPs) can expand freely without damaging the electrode structure. The LMMs-based anodes exhibit superior capacity of rete-performance and ultra-long cycling stability remaining 413 mAh g-1 after 5000 cycles at 5.0 A g-1. Ex situ X-ray powder diffraction (XRD) patterns and electrochemical impedance spectroscopy (EIS) reveal that the LMMs anode displays a stable alloying/de-alloying mechanism. DFT calculations validate the electronic structure and stability of the room-temperature LMMs system. These findings will bring some new opportunities to develop high-performance battery systems.

A Temperature-Tolerant Magnesium-Ion Battery Using Ball Cactus-like MgV2O4 as High-Performance Cathode

Safe and high-performance secondary batteries using for all-climate conditions with different temperatures are highly required. Here, we develop a three-dimensional ball cactus-like MgV2O4 as cathode material for magnesium-ion (Mg-ion) batteries. After cycling 300 times, the capacity maintains 111.7 mAh g-1, while Coulombic efficiency stabilizes at about 100 %. Under temperatures of 45 °C and -5 °C, the capacities remain stable after 200 cycles. After three rounds of rate-performance tests, the capacity keeps quite stable. It is ascribed to the ball cactus-like morphology buffers the volumetric change during Mg2+ insertion/extraction, and provides sufficient pathways for ion diffusion, which has been verified by constant-current intermittent titration technology. It is believed that the good performance enables the Mg-ion batteries to have a all-climate capability.

All-Climate Long-Life and Fast-Charging Sodium-Ion Battery using Co3 S4 @NiS2 Heterostructures Encapsulated in Carbon Matrix as Anode

Sodium-ion (Na-ion) battery is one of the research focuses because of high theoretical capacity and low cost. However, seeking for ideal anodes remains a big challenge. Here, a Co3 S4 @NiS2 /C synthesized by in situ growing NiS2 on CoS spheres then converting to Co3 S4 @NiS2 heterostructures encapsulated by carbon matrix, is developed as a promising anode. Co3 S4 @NiS2 /C as anode displays a high capacity of 654.1 mAh g-1 after 100 cycles. Even over 2000 cycles at a high rate of 10 A g-1 , capacity exceeds 143.2 mAh g-1 . Heterostructures between Co3 S4 and NiS2 improve electron transfer as verified by density functional theory (DFT) calculations. In addition, when cycling at a high temperature of 50 °C, the Co3 S4 @NiS2 /C anode displays 525.2 mAh g-1 , while it remains 340 mAh g-1 at -15 °C, indicating all-climate potential for using under different temperatures.

Long-Cycling-Life Sodium-Ion Battery Using Binary Metal Sulfide Hybrid Nanocages as Anode

Due to the relatively high capacity and lower cost, transition metal sulfides (TMS) as anode show promising potential in sodium-ion batteries (SIBs). Herein, a binary metal sulfide hybrid consisting of carbon encapsulated CoS/Cu2 S nanocages (CoS/Cu2 S@C-NC) is constructed. The interlocked hetero-architecture filled with conductive carbon accelerates the Na+ /e- transfer, thus leading to improved electrochemical kinetics. Also the protective carbon layer can provide better volume accommondation upon charging/discharging. As a result, the battery with CoS/Cu2 S@C-NC as anode displays a high capacity of 435.3 mAh g-1 after 1000 cycles at 2.0 A g-1 (≈3.4 C). Under a higher rate of 10.0 A g-1 (≈17 C), a capacity of as high as 347.2 mAh g-1 is still remained after long 2300 cycles. The capacity decay per cycle is only 0.017%. The battery also exhibits a better temperature tolerance at 50 and -5 °C. A low internal impedance analyzed by X-ray diffraction patterns and galvanostatic intermittent titration technique, narrow band gap, and high density of states obtained by first-principle calculations of the binary sulfides, ensure the rapid Na+ /e- transport. The long-cycling-life SIB using binary metal sulfide hybrid nanocages as anode shows promising applications in versatile electronic devices.

A Lamellar Yolk-Shell Lithium-Sulfur Battery Cathode Displaying Ultralong Cycling Life, High Rate Performance, and Temperature Tolerance

The shuttling behavior and slow conversion kinetics of the intermediate lithium polysulfides are the severe obstacles for the application of lithium-sulfur (Li-S) batteries over a wide temperature range. Here, an engineered lamellar yolk-shell structure of In2 O3 @void@carbon for the Li-S battery cathode is developed for the first time to construct a powerful barrier that effectively inhibits the shuttling of polysulfides. On the basis of the unique nanochannel-containing morphology, the continuous kinetic transformation of sulfur and polysulfides is confined in a stable framework, which is demonstrated by using X-ray nanotomography. The constructed Li-S battery exhibits a high cycling capability over 1000 cycles at 1.0 C with a capacity decay rate as low as 0.038% per cycle, good rate performance, and temperature tolerance at -10, 25, and 50 °C. A nondestructive in situ monitoring method of the interfacial reaction resistance in different cycling stages is proposed, which provides a new analysis perspective for the development of emerging electrochemical energy-storage systems.

A novel rose-with-thorn ternary MoS2@carbon@polyaniline nanocomposite as a rechargeable magnesium battery cathode displaying stable capacity and low-temperature performance

Developing high-performance cathode materials for magnesium (Mg) batteries is of great significance. Here, a novel rose-with-thorn ternary MoS₂@C@polyaniline (PANI) nanocomposite composed of carbon and PANI nanoneedles co-coated on rose-like MoS₂ is developed. The conductive PANI needles on the surface of MoS₂ improve the conductivity, and the inner MoS₂ is wrapped by a carbon layer which is beneficial for the aniline coating. The MoS₂@C@PANI-based Mg battery cathode displays a good capacity of 114 mA h g^-1 after 100 cycles, and a recoverable rate-performance after repeated measurements. In addition, a stable capacity of 105 mA h g^-1 when cycled at a low temperature of -5 °C is also achieved, indicating good potential for applications.