Heterogeneous Effects on Chemo-Mechanical Coupling Behaviors at the Single-Particle Level

Understanding and alleviating the chemo-mechanical degradation of silicon anodes is a formidable challenge due to the large volume change during operations. Here, for a comprehensive understanding of heterogeneous effects on chemo-mechanical behaviors at the single-particle level, in-situ observation of single-crystalline silicon micropillar electrodes under the inhomogeneous extrinsic conditions, taken as an example, was made. The observation shows that the anisotropic deformation patterns and fracture starting sites are reshaped with the combination of the inhomogeneous electrochemical driving force for charge transfer at the interface between the silicon micropillar and the electrolyte, and crystal orientation-dependent lithiation dynamics. Also, the numerical simulation unravels the underlying mechanisms of deformation and fracture behaviors, and well predicts the relative depth of lithiation at the time of crack initiation under heterogeneous conditions. The results show that heterogeneities arising from extrinsic conditions may induce inhomogeneous mechanical damage and tailor lithiation degree at an active particle level, offering insights into designing large-volume-change battery particles with good mechanical integrity and electrochemical performance under heterogeneous impacts.

Deposited Layers as Negative Electrodes for Lithium Ion Batteries

The battery usage increases every year. The batteries help with development of mobility both from point of view of portable electronic and from view of goods and people transport in electromobility. One of the main parameters is gravimetric and volumetric capacity, which we are trying continually increase. One of the main ways is to change current used material by new ones with better parameters. One of possibilities is to use thin layer and so-called battery conversion principle. Electrodes works on conversion principle have usual higher capacities. The main disadvantage of such system is large volume change of electrode material due charging and discharging. This can be partly solved by special 3D structure which compensate the volume changes. This work focusses on preparing basic thin layer electrode by help of electrodeposition. The electrodes are then cycled against lithium.

Investigation on Fabrication of Reduced Graphene Oxide-Sulfur Composite Cathodes for Li-S Battery via Hydrothermal and Thermal Reduction Methods

Lithium-sulfur (Li-S) battery is considered one of the possible alternatives for next-generation high energy batteries. However, its practical applications are still facing great challenges because of poor electronic conductivity, large volume change, and polysulfides dissolution inducing “shuttle reaction” for the S cathode. Many strategies have been explored to alleviate the aforementioned concerns. The most common approach is to embed S into carbonaceous matrix for constructing C-S composite cathodes. Herein, we fabricate the C-S cathode reduced graphene oxide-S (rGO-S) composites via one step hydrothermal and in-situ thermal reduction methods. The structural features and electrochemical properties in Li-S cells of the two type rGO-S composites are studied systematically. The rGO-S composites prepared by one step hydrothermal method (rGO-S-HT) show relatively better comprehensive performance as compared with the ones by in-situ thermal reduction method (rGO-S-T). For instance, with a current density of 100 mA g−1, the rGO-S-HT composite cathodes possess an initial capacity of 1290 mAh g−1 and simultaneously exhibit stable cycling capability. In particular, as increasing the current density to 1.0 A g−1, the rGO-S-HT cathode retains a reversible capacity of 582 mAh g−1 even after 200 cycles. The enhanced electrochemical properties can be attributed to small S particles uniformly distributed on rGO sheets enabling to significantly improve the conductivity of S and effectively buffer large volume change during lithiation/delithiation.

An SiOx anode strengthened by the self-catalytic growth of carbon nanotubes

A close-knit CNTs coating that in-situ grown on the SiOx particles realizes the “soft-combination” between SiOx and CNTs, thus conquering the long-lasting issues of poor conductivity and large volume change of SiOx faced.

Construction of molybdenum vanadium oxide/nitride hybrid nanoplate arrays for aqueous zinc-ion batteries and reliable insights into reaction mechanism

Vanadium (V)-based cathode materials hold great potential for rechargeable aqueous zinc-ion batteries (AZIBs). However, the shortcomings of poor electrical conductivity, large volume change, serious V dissolution and complicated electrochemical reaction...

N-doped carbon encapsulating Bi nanoparticles derived from metal-organic framework for high-performance sodium-ion batteries

Bismuth (Bi), as an alloy-based material, has been demonstrated as a promising anode for sodium-ion batteries (SIBs) due to its high theoretical capacity. However, the large volume change of Bi...

Cu2Se Nanoparticles Encapsulated by Nitrogen-Doped Carbon Nanofibers for Efficient Sodium Storage

Cu2Se with high theoretical capacity and good electronic conductivity have attracted particular attention as anode materials for sodium ion batteries (SIBs). However, during electrochemical reactions, the large volume change of Cu2Se results in poor rate performance and cycling stability. To solve this issue, nanosized-Cu2Se is encapsulated in 1D nitrogen-doped carbon nanofibers (Cu2Se-NC) so that the unique structure of 1D carbon fiber network ensures a high contact area between the electrolyte and Cu2Se with a short Na+ diffusion path and provides a protective matrix to accommodate the volume variation. The kinetic analysis and DNa+ calculation indicates that the dominant contribution to the capacity is surface pseudocapacitance with fast Na+ migration, which guarantees the favorable rate performance of Cu2Se-NC for SIBs.

Bio-Inspired Soft Swim Bladders of Large Volume Change Using Dual Dielectric Elastomer Membranes

The buoyancy control mechanism is critical for undersea robots to achieve effective vertical motion. However, current buoyancy control mechanisms are associated with problems such as complex design, bulky structure, noisy operation, and slow response. Inspired by the swim bladder of natural fish, we develop an artificial swim bladder, using dual membranes of the dielectric elastomer, which exhibit interesting attributes, including fast response, light weight, silent operation, especially large volume change. Both the experiments and theoretical simulations are conducted to analyze the performance of this artificial swim bladder, and they quantitatively agree with each other. This artificial swim bladder of dual membranes is capable of large voltage-induced volume change, 112% larger than the conventional single-membrane design. Consequently, this soft actuator can generate a buoyancy force of 0.49 N. This artificial swim bladder demonstrates effective up-and-down motion in water, due to its large reversible volume change. Future work includes adding horizontal-motion and turning capabilities to the existing robotic structure, so that the soft robotic fish can achieve successful navigation in undersea environments.

N-Doped carbon coated bismuth nanorods with a hollow structure as an anode for superior-performance potassium-ion batteries

We designed the Bi nanorods encapsulated in N-doped carbon tubes with hollow structure, which can limit the large volume change during the potassiation process. The composite exhibits superior electrochemical performance as anode for K-ion batteries.