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—Machine learning technologies have gained significant popularity in rechargeable battery research in recent years, and have been extensively adopted to construct data-driven solutions to tackle multiple challenges for energy storage in embedded computing systems. An important application in this area is the machine learning-based battery lifetime prediction, which formulates regression models to estimate the remaining lifetimes of batteries given the measurement data collected from the testing process. Due to the non-idealities in practical operations, these measurements are usually impacted by various types of interference, thereby involving noise on both input variables and regression labels. Therefore, existing works that focus solely on minimizing the regression error on the labels cannot adequately adapt to the practical scenarios with noisy variables. To address this issue, this study adopts total least squares (TLS) to construct a regression model that achieves superior regression accuracy by simultaneously optimizing the estimation of both variables and labels. Furthermore, due to the expensive cost for collecting battery cycling data, the number of labeled data samples used for predictive modeling is often limited. It, in turn, can easily lead to overfitting, especially for TLS, which has a relatively larger set of problem unknowns to solve. To tackle this difficulty, the TLS method is investigated conjoined with stepwise feature selection in this work. Our numerical experiments based on public datasets for commercial Lithium-Ion batteries demonstrate that the proposed method can effectively reduce the modeling error by up to 11.95 %, compared against the classic baselines with consideration of noisy measurements. • Studied battery lifetime prediction considering the noise on input variables induced by practical non-idealities. • Leveraged total-least-squares regression to simultaneously optimize the estimation of both variables and labels. • Developed stepwise feature selection method to tackle the overfitting issue induced by the shortage of data. • Conducted numerical experiments based on public datasets to demonstrate the improvement of prediction accuracy. [ABSTRACT FROM AUTHOR]

[Display omitted] • NiM (M: Sb, Sn)/nitrogen-doped hollow carbon tubes (NiM-C) structure was constructed. • NiM-C displays exciting capacity and rate performance for lithium ion batteries. • Electrochemical analysis reveals the lithium storage behavior of NiM-C during cycling. Alloy-type materials are regarded as prospective anode replacements for lithium-ion batteries (LIBs) owing to their attractive theoretical capacity. However, the drastic volume expansion leads to structural collapse and pulverization, resulting in rapid capacity decay during cycling. Here, a simple and scalable approach to prepare NiM (M: Sb, Sn)/nitrogen-doped hollow carbon tubes (NiM C) via template and substitution reactions is proposed. The nanosized NiM particles are uniformly anchored in the robust hollow N -doped carbon tubes via Ni N C coordination bonds, which not only provides a buffer for volume expansion but also avoids agglomerating of the reactive material and ensures the integrity of the conductive network and structural framework during lithiation/delithiation. As a result, NiSb C and NiSn C exhibit high reversible capacities (1259 and 1342 mAh/g after 100 cycles at 0.1 A/g) and fascinating rate performance (627 and 721 mAh/g at 2 A/g), respectively, when employed as anodes of LIBs. The electrochemical kinetic analysis reveals that the dominant lithium storage behavior of NiM C electrodes varies from capacitive contribution to diffusion contribution during the cycling corresponding to the activation of the electrode exposing more NiM sites. Meanwhile, M (Sb, Sn) is gradually transformed into stable NiM during the de-lithium process, making the NiM C structure more stable and reversible in the electrochemical reaction. This work brings a novel thought to construct high-performance alloy-based anode materials. [ABSTRACT FROM AUTHOR]

• V 2 O 5 · n H 2 O/rGO was synthesized via a dual electrostatic assembly strategy. • The synergistic contribution in the composite improves the energy storage ability. • The composite exhibits excellent rate capability when used as cathode for LIBs. As well-known, hydrated vanadium pentoxide (V 2 O 5 · n H 2 O) has a larger layer spacing than orthogonal V 2 O 5 , which could offer more active sites to accommodate lithium ions, ensuring a high specific capacity. However, the exploration of V 2 O 5 · n H 2 O cathode is limited by its inherently low conductivity and slow electrochemical kinetics, leading to a significant decrease in capability. Herein, we prepared V 2 O 5 · n H 2 O/reduced graphene oxide (rGO) composite with low rGO content (8 wt%) via a simple yet effective dual electrostatic assembly strategy. When used as the cathode material for lithium-ion batteries (LIBs), V 2 O 5 · n H 2 O/rGO manifests a high reversible capacity of 268 mAh g−1 at 100 mA g−1 and especially an excellent rate capability (196 mAh g−1 at 1000 mA g−1 and 129 mA h g−1 at 2000 mA g−1), surpassing those of the V 2 O 5 /carbon composites reported in the literatures. Notably, the remarkable performance should be referable to the synergetic effects between one-dimensional V 2 O 5 · n H 2 O nanobelts and two-dimensional rGO nanosheets, which provide a short transport pathway and enhanced electrical conductivity. This strategy opens a new opportunity for designing high-performance cathode material with excellent rate performance for advanced LIBs. [ABSTRACT FROM AUTHOR]

A novel composite containing CoSe and porous carbon polyhedra (PCP), denoted as CoSe@PCP, was successfully synthesized using Co-based zeolitic imidazolate framework (ZIF-67) as precursor through a two-step method, including carbonization of ZIF-67 and subsequent selenization. The field-emission scanning electron microscopy and transmission electron microscopy characterizations confirm that CoSe nanoparticles are uniformly dispersed in PCP. When the CoSe@PCP was used as anode material for lithium-ion batteries, it exhibits superior performance with a high reversible capacity of 675 mAh g −1 at 200 mA g −1 after 100 cycles and 708.2 mAh g −1 at 1 A g −1 after 500 cycles as well as excellent cycling stability. Additionally, the CoSe@PCP also demonstrates excellent performance as anode material for sodium-ion batteries. A reversible capacity of 341 mAh g −1 can be obtained over 100 cycles at 100 mA g −1 with high cycling stability. The excellent battery performance of CoSe@PCP should be attributed to the synergistic effect of nanostructured CoSe and PCP derived from ZIF-67, in which the nanostructured CoSe possesses high reactivity towards lithium and sodium ions and the PCP can provide a continuous conductive matrix to facilitate the charge transfer and an effective buffering to mitigate the structure variation of CoSe during cycling. [ABSTRACT FROM AUTHOR]

[Display omitted] Metal sulfides are recognized as potential candidates for the anode materials of lithium ion batteries (LIBs) because of their high theoretical capacity. However, the low reaction kinetics of metal sulfides leads to their poor cycle life and rate performance, which limits their practical application in the field of energy storage. In this work, we synthesized a self-assembled carbon-free vanadium sulfide (V 3 S 4) nanosheet via a facile and efficient method. The unique mesoporous nanostructure of V 3 S 4 can not only accelerate the migration of ions/electrons, but also alleviate the volume expansion during the lithium ion insertion/extraction process. When used as the anode material of LIBs, the carbon-free V 3 S 4 electrode exhibits remarkable electrochemical performance with ultra-high charge capacity (1099.3 mAh g−1 at 0.1 A g−1), superior rate capability (668.8 mAh g−1 at 2 A g−1 and 588.8 mAh g−1 at 5 A g−1) and impressive cycling ability (369.6 mAh g−1 after 200 cycles at 10 A g -1), which is very competitive compared with those of most metal sulfides-based anode materials reported so far. The strategy in this work provides inspiration for the rational design of advanced nanostructured electrode materials for energy storage devices. [ABSTRACT FROM AUTHOR]

[Display omitted] Rational construction of hybrid materials integrating the collective virtues of individual building blocks has spurred significant interest in electrode materials for energy storage. Herein, a smart hybrid was fabricated via in-situ assembling of the few-layered MoS 2 (f-MoS 2) coated on the multi-layered Ti 3 C 2 MXene decorated with the TiO 2 nanoparticles by the scalable hydrothermal and annealing approaches. In the unique architecture, the multi-layered Ti 3 C 2 with the expanded interspaces as the conductive backbone can facilitate the electron transport, provide adequate space to facilitate the infiltration of organic electrolyte into the interior of electrode, and inhibit the aggregation of MoS 2 nanosheets, while the f-MoS 2 with enlarged interlayer can be beneficial for the lithium-ion diffusion and prevent the multi-layered Ti 3 C 2 from restacking. Moreover, the TiO 2 decorated on the Ti 3 C 2 can effectively inhibit the instability of long-chain lithium polysulfides dissolved in organic electrolyte to improve the cycling stability. Thanks to the synergistic effect of the building blocks, the Ti 3 C 2 /TiO 2 @f-MoS 2 hybrid employed as lithium storage anode delivers an extraordinary endurable ability with a high storage capacity of 403.1 mA h g−1 after 1200 cycles at 2 A g−1. Importantly, the smart hybridization strategy in this work paves an efficient way to explore the high-performance MXene-based hybrid materials in energy storage fields. [ABSTRACT FROM AUTHOR]

• FTOC/MXene was fabricated by combining MXene, C and (Fe 2.5 Ti 0.5) 1.04 O 4. • FTOC/MXene shows a unique two-dimensional architecture. • FTOC/MXene exhibits a superior rate performance as anode for LIBs. • The effects on restricting the volume expansion during cycling have been studied. The development of battery systems with high specific capacity and power density could fuel various energy-related applications from personal electronics to grid storage. (Fe 2.5 Ti 0.5) 1.04 O 4 possessing high theoretical specific capacity has been considered as a promising high rate anode material for lithium ion batteries due to the replacement of Fe3+ (0.64 Å) by Ti4+ (0.68 Å) with a larger radius to expand the interlayer space for ion intercalation. However, its extreme volume variation upon cycling as well as poor electrical conductivity hinder its further application. To tackle the above problems, in this work, we successfully synthesized two-dimensional (2D) (Fe 2.5 Ti 0.5) 1.04 O 4 /C/MXene architecture derived from Ti 3 C 2 T x MXene via solvo-hydrothermal, ultrasound hybridizing and high temperature annealing processes. The (Fe 2.5 Ti 0.5) 1.04 O 4 /C/MXene shows a high discharge capacity of 757.2 mAh g−1 after 800 cycles at a current density of 3 A g−1 with excellent rate performance. The superior electrochemical performances are triggered primarily by the incorporation of carbon and MXene into (Fe 2.5 Ti 0.5) 1.04 O 4 moiety to construct a 2D layered structure, which can improve the ion diffusion and electron transport. In addition, the synergistic contributions from diffusion controlled and capacitive processes for (Fe 2.5 Ti 0.5) 1.04 O 4 /C/MXene improve the ion diffusion rate and offer high specific capacity at high current density. The MXene-derived synthesis strategy in this work should be a promising pathway to synthesize other anode materials with 2D layered architecture for high performance lithium storage. [ABSTRACT FROM AUTHOR]

• N, S co-doped V 2 CT x MXene was prepared and its structure was optimized. • N, S co-doped V 2 CT x MXene exhibited superior electrochemical performances for LIBs. • The lithium storage mechanism of N, S co-doped V 2 CT x MXene was investigated. As an emerging group of two-dimensional (2D) layered material, MXenes have received significant attention in the direction of energy storage. However, the restacking of MXene flakes severely hinders the ion transport within electrodes, which limits their application for lithium-ion batteries (LIBs). To address this issue, herein, we rationally designed and optimized the structure of N, S co-doped V 2 CT x MXene, which exhibits excellent electrochemical performance with a high reversible capacity of 590 mAh g−1 after 100 cycles at 0.1 A g−1 when used as anode of LIBs. Even at a high current density of 2 A g−1, a reversible capacity of 298 mAh g−1 is obtained after 300 cycles, which outperforms most of the V 2 CT x -based anode materials reported so far. The lithium-ion storage mechanism of N, S co-doped V 2 CT x MXene was studied by a series of characterizations. The results show that the significant improvement of electrochemical performance should be attributed to the facilitated charge transfer after N and S co-doping in V 2 CT x MXene, which can effectively improve the ion transfer kinetics during the lithiation-delithiation process. Furthermore, the expanded interlayer spacing of N, S co-doped V 2 CT x provides more active sites for the adsorption of lithium ions, promoting the insertion capacity of lithium ions. This work indicates that the N, S co-doped 2D V 2 CT x MXene should be a promising anode material for high-performance LIBs. [ABSTRACT FROM AUTHOR]

Iron carbide (Fe 3 C) has become a significant type of anode material for lithium-ion batteries (LIBs) due to its intrinsic catalytic ability for the reversion of solid electrolyte interface (SEI) film. However, the low electrical conductivity and structural instability still hinder its practical application. The combination of Fe 3 C with highly conductive matrix is effective at addressing this issue. In this work, nano-Fe 3 C decorated N, S co-doped carbon nanotubes (Fe 3 C-NSC) was synthesized through a facile one-pot in-situ growth method. Benefiting from the synergetic effects between nano-Fe 3 C and N, S co-doped carbon nanotubes, Fe 3 C-NSC demonstrated an ultrahigh reversible capacity of 926 mAh g−1 at 100 mA g−1 after 100 cycles, and maintained a reversible capacity of 510.9 mAh g-1 at 500 mA g−1 after 900 cycles. Even when operated at −20 °C, Fe 3 C-NSC still delivered 373.4 mAh g−1 at 100 mA g−1 after 100 cycles. The strategy in this work should provide new insight into Fe 3 C-based anode of LIBs. [Display omitted] • Fe 3 C nanocrystals are decorated on N, S co-doped carbon nanotubes. • A facile one-pot in-situ growth strategy is developed. • The composite was evaluated as anode of lithium-ion batteries. • The composite demonstrates ultrahigh reversible capacity at both room and low temperature. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Covalent organic frameworks (COFs) with devisable nanostructures have exhibited extensive application prospects in energy storage and conversion. In this work, spherical COFs were successfully utilized as an ideal precursor for N, B co-doped carbon spheres (NBCs) that display hierarchical spherical architectures with rich pores. When applied as lithium ion batteries (LIBs) anode, NBCs exhibit high reversible specific capacity and outstanding long-life cycling stability (205.5 mAh g−1 at 5.0 A g−1 and 171.4 mAh g−1 at 10.0 A g−1 after 5000 cycles) owing to their hierarchical porosity, unique structure and in-situ N, B co-doping. The excellent lithium storage ability, especially satisfactory long cycling stability, enables NBCs to be a promising candidate for LIBs. [ABSTRACT FROM AUTHOR]

Abstract Pursuing active, stable, low-cost and well-designed electrode materials with superior rate capability and long-life cycling performance for lithium-ion batteries (LIBs) remains a big challenge. In this work, shuttle-like hollow and porous carbon-coated FeP (FeP@C) structures were synthesized from Fe-based metal-organic frameworks (MOFs) MIL-88 as precursors and used as anodes for LIBs. The FeP@C displays a unique structure with ultrafine FeP nanoparticles distributed in the hollow and porous carbon matrix, which offers large specific surface area and fast charge transfer ability, and alleviates volume change during cycling. As a result, the FeP@C delivers a high maximum lithium storage capacity (902.4 mAh g−1 at 0.1 A g−1 for 100 cycles), superior rate capability (reversible capacity of 416 mAh g−1 at 5.0 A g−1) and long-life cycling performance (3000 cycles at 5.0 A g−1). The excellent electrochemical performance is related to significant contribution of pseudocapacitive behavior during charge/discharge process, especially at high current density. The current strategy should be promising to synthesize the carbon-coated porous structure from MOFs for next-generation energy-storage application. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Smart design and rational fabrication of novel anode materials with high specific capacity and long cycling stability are of significant importance for high-performance lithium-ion batteries (LIBs). Herein, nanostructured ZnO/NiO microspheres with a nanorods-composed shell and a microsphere yolk were synthesized by a controlled calcination treatment of the bimetallic organic frameworks in air. The obtained yolk-shell ZnO/NiO microspheres are observed to have an average diameter of 2 μm with uniform microsphere morphology from field-emission scanning electron microscopy and high-resolution transmission electron microscopy. Benefitting from the unique yolk-shell structure inherited from the bimetallic organic frameworks and the synergistic effect from ZnO and NiO, the as-prepared yolk-shell ZnO/NiO displays excellent lithium storage performance, including high specific capacity (1008.6 mAh g −1 at 0.1 A g −1 after 200 cycles), superior rate capability (437.1 mAh g −1 at 2 A g −1 ) and outstanding long-term cycling stability (592.4 mAh g −1 at 0.5 A g −1 after 1000 cycles), which demonstrates its promising potential as high-performance anode material for LIBs. [ABSTRACT FROM AUTHOR]

In this work, porous NiO microspheres interconnected by carbon nanotubes (NiO/CNTs) were successfully fabricated by the pyrolysis of nickel metal-organic framework precursors with CNTs and evaluated as anode materials for lithium-ion batteries (LIBs). The structures, morphologies, and electrochemical performances of the samples were characterized by X-ray diffraction, N2 adsorption-desorption, field emission scanning electron microscopy, cyclic voltammetry, galvanostatic charge/discharge tests, and electrochemical impedance spectroscopy, respectively. The results show that the introduction of CNTs can improve the lithium-ion storage performance of NiO/CNT composites. Especially, NiO/CNTs-10 exhibits the highest reversible capacity of 812 mAh g−1 at 100 mA g−1 after 100 cycles. Even cycled at 2 A g−1, it still maintains a stable capacity of 502 mAh g−1 after 300 cycles. The excellent electrochemical performance of NiO/CNT composites should be attributed to the formation of 3D conductive network structure with porous NiO microspheres linked by CNTs, which benefits the electron transfer ability and the buffering of the volume expansion during the cycling process. [ABSTRACT FROM AUTHOR]

The main challenge of using TiO 2 as anode for sodium-ion batteries (SIBs) is its inherent low electrical conductivity, which leads to its unsatisfied capacity, short cycle life and low initial Coulombic efficiency. Herein, we report that synergistically doped anatase TiO 2 nanotubes with Ni and N via a simple sol-gel process, subsequent alkali-thermal reaction, and final thermal treatment in NH 3 can optimize the relationship among the phase structure, electrical conductivity and sodium-ion diffusion kinetic performance of anatase TiO 2 to enhance its sodium-ion storage and transport performances. The resultant Ni and N co-doped anatase TiO 2 nanotubes (Ni-N/TNTs) exhibit a high charge capacity of 303 mA h g −1 after 500 cycles at a current density of 50 mA g −1 with an initial Coulombic efficiency of 65% and even at a high current density of 5 A g −1 , a capacity of 143 mA h g −1 is maintained after 8000 cycles with a capacity retention of ≥100%. The bandgap estimation, phase structure evolution, and electrochemical impedance spectroscopy analysis combined with the electrochemical test results indicate that the significantly improved sodium-ion storage and transport performances of Ni-N/TNTs should be mainly ascribed to the increased electrical conductivity, stable phase structure during the electrochemical processes, lower charge transfer resistance, and enhanced sodium-ion diffusion coefficient after Ni and N co-doping. The high capacity, improved Coulombic efficiency, excellent rate performance and long cycle life enable Ni-N/TNTs to be an applicable anode material for SIBs. [ABSTRACT FROM AUTHOR]

N-doped porous carbon materials (NPCs) were prepared by the carbonization of covalent-organic frameworks as precursors and used as anodes for lithium and sodium ion batteries (LIBs and SIBs) for the first time. The morphology, structure and electrochemical performance were characterized and evaluated by field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, nitrogen adsorption and desorption isotherms, galvanostatic charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy, respectively. The NPCs not only show high maximum reversible charge capacities of 488 mAh g −1 at 100 mA g −1 (LIBs) and 237.7 mAh g −1 at 50 mA g −1 (SIBs) after 100 cycles, but also deliver high reversible charge capacities of 143 mAh g −1 at 5 A g −1 (LIBs) and 88.8 mAh g −1 at 2.5 A g −1 (SIBs) and excellent rate performance. Moreover, superior long-life cycling stability is observed for 5000 cycles even at a very high current density of 5 A g −1 for LIBs and 2.5 A g −1 for SIBs. The excellent electrochemical performance of NPCs with superior reversible capacity, good rate performance, and long-life cycling stability is attributed to their N doping, high specific surface area and porous structure with large interlayer distance. [ABSTRACT FROM AUTHOR]

Traditional lithium-ion batteries that are based on layered Li intercalation electrode materials are limited by the intrinsically low theoretical capacities of both electrodes and cannot meet the increasing demand for energy. A facile route for the synthesis of a new type of composite nanofibers, namely carbon nanofibers decorated with molybdenum disulfide sheets (CNFs@MoS2), is now reported. A synergistic effect was observed for the two-component anode, triggering new electrochemical processes for lithium storage, with a persistent oxidation from Mo (or MoS2) to MoS3 in the repeated charge processes, leading to an ascending capacity upon cycling. The composite exhibits unprecedented electrochemical behavior with high specific capacity, good cycling stability, and superior high-rate capability, suggesting its potential application in high-energy lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Traditional lithium-ion batteries that are based on layered Li intercalation electrode materials are limited by the intrinsically low theoretical capacities of both electrodes and cannot meet the increasing demand for energy. A facile route for the synthesis of a new type of composite nanofibers, namely carbon nanofibers decorated with molybdenum disulfide sheets (CNFs@MoS2), is now reported. A synergistic effect was observed for the two-component anode, triggering new electrochemical processes for lithium storage, with a persistent oxidation from Mo (or MoS2) to MoS3 in the repeated charge processes, leading to an ascending capacity upon cycling. The composite exhibits unprecedented electrochemical behavior with high specific capacity, good cycling stability, and superior high-rate capability, suggesting its potential application in high-energy lithium-ion batteries. [ABSTRACT FROM AUTHOR]

• A facile in-situ strategy was developed to synthesize g-C 3 N 4 /Mo 2 CT x hybrid. • Further exfoliating Mo 2 CT x and constructing g-C 3 N 4 protection layer was realized. • g-C 3 N 4 /Mo 2 CT x exhibits much improved Coulombic efficiency and cycling stability. Mo 2 CT x MXene, obtained by etching Ga from the Mo 2 Ga 2 C, is theoretically predicted to possess high electrochemical activity. However, the preparation of Mo 2 CT x remains challenging due to the difficultly of traditional HF etching. Increasing the exfoliation degree and constructing the protection layer of Mo 2 CT x not only can offer rich active sites but also suppress side reaction, which has been considered as efficient approaches to improving its electrochemical performance. In this work, a facile in-situ strategy was developed to synthesize the graphitic carbon nitride/Mo 2 CT x (g-C 3 N 4 /Mo 2 CT x) hybrid, smartly employing the conversion from urea to g-C 3 N 4 to realize the exfoliation degree of Mo 2 CT x MXene and simultaneously build a protection layer. As expected, the abundant exposed MXene layers are believed to provide rapid diffusion pathways for the ions transport as well as rich active sites for lithium storage. As a result, the target g-C 3 N 4 /Mo 2 CT x hybrid exhibits a much higher Coulombic efficiency (70.8%) and superior lithium storage performance (525.8 mAh g−1) compared with pure Mo 2 CT x (19.2% and 101.4 mAh g−1). Generally, this synthesis strategy presented in this study paves a new way for the fabrication of MXene based hybrid with high performance for lithium storage. [ABSTRACT FROM AUTHOR]

• 3D TiO 2 @NC/Fe 7 S 8 was fabricated by combining urchin-like TiO 2 , NC and Fe 7 S 8. • TiO 2 @NC/Fe 7 S 8 exhibits excellent lithium storage capability as anode material. • The superior performance is due to synergistic effect between TiO 2 , NC and Fe 7 S 8. Nowadays, Ti 3 C 2 T x MXene has been reported to afford an ideal platform for the growth of TiO 2 by oxidation. Unfortunately, the TiO 2 derived from Ti 3 C 2 T x still possesses low lithium ion diffusion coefficient, poor electrical conductivity and relatively inferior capacity when used as anode of rechargeable lithium ion batteries (LIBs). In this work, three dimensional (3D) TiO 2 @nitrogen-doped carbon (NC)/Fe 7 S 8 composite was fabricated by a facile and simple hybrid strategy via in situ polymerization of pyrrole monomer with alkalized Ti 3 C 2 T x and subsequent vulcanization at 700 °C. When evaluated as an anode material for LIBs, the TiO 2 @NC/Fe 7 S 8 demonstrates a high reversible capacity (516 mAh g−1 after 100 cycles at 0.1 A g−1), excellent rate capability (337 mAh g−1 at 1 A g−1) and robust long cycling stability (282 mAh g−1 after 1000 cycles at 4 A g−1). The excellent electrochemical performances are contributed by the unique architecture of TiO 2 @NC/Fe 7 S 8 , where 3D urchin-like TiO 2 with good structural stability provides adequate space to increase the contact between electrode and electrolyte, shorten the lithium ion diffusion length and alleviate the volume change; nitrogen-doped carbon shell layer improves the electrical conductivity, facilitates the electron transport and prevents the aggregation for Fe 7 S 8 ; Fe 7 S 8 contributes high specific capacity during charge/discharge process. Importantly, the hybrid approach in this work enlightens the exploration on combing the MXene-derived oxides with other metal sulfides for promising applications in energy storage field. [ABSTRACT FROM AUTHOR]

• The unique SnS 2 /Sn 3 S 4 -Ti 3 C 2 composites were studied as anode material of LIBs. • The SnS 2 /Sn 3 S 4 hybrid and Ti 3 C 2 MXene display high synergetic effects. • The SnS 2 /Sn 3 S 4 -Ti 3 C 2 composites demonstrate superior rate performance. The combination of transitional metal dichalcogenides with MXene is an effective strategy to explore high-performance anode materials for lithium-ion batteries (LIBs). In this work, SnS 2 /Sn 3 S 4 hybrid decorated on Ti 3 C 2 MXene (S-TC) was prepared through a facile solvothermal and calcination process. The multi-layered Ti 3 C 2 matrix improves the electron transport capability, inhibits the aggregation and accommodates the volume change of SnS 2 /Sn 3 S 4 hybrid, while the SnS 2 /Sn 3 S 4 hybrid confined in the multilayer stacks serves as a spacer to decrease the tendency of layer restacking and improves the limited capacities of Ti 3 C 2. Besides, the nano-sized SnS 2 /Sn 3 S 4 hybrid with high specific surface area also enhances the contact between electrolyte and electrode. When used as anode for LIBs, S-TC demonstrates a good cycling stability (462.3 mAh g−1 at 100 mA g−1 after 100 cycles) and superior rate performance (216.5 mAh g−1 at 5000 mA g−1). The strategy in this work should provide a new insight into fabricating novel MXene-based anode material for high-rate LIBs. [ABSTRACT FROM AUTHOR]

• Ni 3 S 2 in-situ encapsulated in nitrogen doped carbon networks was fabricated. • The encapsulation improves the electrical and ionic conductivities of Ni 3 S 2 @NC. • The Ni 3 S 2 @NC exhibits excellent reversible capacity and superior cycling stability. Due to the conversion reaction induced high specific capacity, low cost and rich types, the interest on transition metal sulfides for efficient lithium storage has grown. Unfortunately, the intrinsically poor electrical conductivity and structure instability restrict their practical applications. Herein, an in-situ encapsulation strategy is developed to prepare the Ni 3 S 2 nanoparticles encapsulated in interconnected N-doped porous carbon (Ni 3 S 2 @NC) through a facile freeze-drying approach and subsequent in-situ conversion. When evaluated as anode material for lithium-ion batteries (LIBs), the as-prepared Ni 3 S 2 @NC exhibits a remarkable lithium storage performance, including high reversible capacity (1335.4 mAh g−1 after 100 cycles at 0.1 A g−1), superior rate capability (507.7 mAh g−1 at 4 A g−1) and excellent long-term cycling stability (961.4 mAh g−1 after 600 cycles at 0.5 A g−1 and 862.8 mAh g−1 after 600 cycles at 1 A g−1), displaying one of the best lithium storage performances among the Ni 3 S 2 -based electrodes reported by now. Such an excellent lithium storage performance should be attributed to the unique structure advantages of Ni 3 S 2 @NC inherited from the in-situ encapsulation strategy, such as tight combination, increased electrical conductivity, shortened ion diffusion distance and buffering matrix provided by N-doped porous carbon networks. Importantly, the facile design and engineering strategy should also be applied to explore other nanoarchitectures to boost their lithium storage performances. [ABSTRACT FROM AUTHOR]