Binder-free Anode For Lithium-ion Batteries Research Articles

Flexible and crosslinking electrospun porous carbon nanofiber membranes as freestanding binder-free anodes for lithium-ion batteries

Electrospinning carbon nanofibers with one-dimensional nanostructures have enormous potential for electronic applications owing to their flexibility, electrical conductivity, high surface area and attractive structure. In this paper, porous nitrogen-doped carbon nanofiber membranes with chemical crosslinking structure (PNCNMs-CC) were prepared for lithium-ion batteries anodes by crosslinking treatment and carbonization process using polyimide as precursor, melamine as nitrogen source and ethyl orthosilicate as pore-forming agent. The heightened nitrogen content synergizes with the augmented specific surface area, engendering a striking electrochemical enhancement. Rich pore structure provides more active sites. When utilized as a binder-free, current collector-free anode, PNCNMs-CC shows an excellent rate performance and long cycle stability. The first discharge specific capacity of PNCNMs-CC delivered 710 mAh g−1 at 50 mA g−1. After 1000 cycles at a high current density of 1 A g−1, PNCNMs-CC shows 88 % capacity retention, demonstrating a promising candidate as the flexible anodes for high-performance energy storage devices.

Bi2Se3@SWCNT heterostructures with beyond theoretical capacity as perspective binder-free anodes for lithium-ion batteries

Bi2Se3 has shown potential for implementation as an anode material for lithium-ion batteries (LIBs), however, the significant volume expansion and dissolution of selenium pose major challenges. In this work, Bi2Se3 nanostructures are synthesized by physical vapor deposition directly on top of a single-wall carbon nanotube (SWCNT) network to fabricate a binder-free Bi2Se3@SWCNT anode materials with different Bi2Se3/SWCNT ratios. Nanostructuring the Bi2Se3 directly on the top of the SWCNT network provides a large accessible contact area and improves mechanical and electrical contact. The heterostructures exhibit capacity, that is beyond the theoretical of pristine Bi2Se3, which can be attributed to the binding of the Se to C, resulting in the resilience against the dissolution of Se, while providing additional electron transport pathways and increased capacitive contribution. A Bi2Se3@SWCNT anode with a mass ratio of (1:1) has the highest capacity in a half-cell after 100 cycles (523 mAh g−1 at 0.1 A g−1) and shows excellent capacity retention after 500 cycles at large current densities (2 A g−1 and 5 A g−1): 1080 mAh g−1 and 809 mAh g−1 respectively. In addition, in a full-cell system Bi2Se3@SWCNT (1:1) delivers high reversible capacity after 150 cycles (484 mAh g−1) at 0.4 A g−1.

Flexible electrode of Fe-doped NiSe2@porous graphene as binder-free anode for lithium-ion batteries

Fe-doped NiSe2@porous graphene is prepared via filtration, annealing, and selenylation. The interfacial interaction between graphene and NiSe2 is enhanced by Fe doping and facilitates the transfer of lithium ions and electrons.

Pliable electrode of porous graphene-encapsulated FeNiSe4 binary-metal selenide nanorods as a binder-free anode for lithium-ion batteries

The FeNiSe4@porous graphene is prepared via filtration, annealing, and selenylation. The synergistic effect of iron and nickel in FeNiSe4@PG contributes to the rapid diffusion of lithium ions and the transport of electrons.

A hybrid flexible N-doped candle-soot carbon nanofibers for binder-free lithium-ion battery anode

This work demonstrates a unique fractal-like candle soot-derived carbon nanoparticles (CSC) decorated onto nitrogen-doped carbon nanofibers (CSC@N-CNFs) by a one-step electrospinning process as a self-standing flexible anode for lithium-ion battery (LIB). The CSC nanoparticles exhibit a short-range ordered structure with large interlayer spacing for enhanced Li ion storage. In addition, the N-CNFs provide flexibility and stability to prevent volume expansion during electrochemical reactions. The synergistic impact of the hybrid structure provides the flexible anode with a high initial discharge capacity of 1030 mAh/g at 0.1C with an outstanding coulombic efficiency of ∼100% at 30C (5 A/g). The enhanced performance is due to the increased electrical conductivity from N-doping from CNFs, the hard carbon morphology of CSC nanoparticles, the 3D interconnected nanofiber framework, and the binder-free flexible nature.

Cobalt Oxide Arrays Anchored to Copper Foam as Efficient Binder-free Anode for Lithium Ion Batteries.

The development of lithium-ion batteries with simplified assembling steps and fast charge capability is crucial for current battery applications. In this study, we propose a simple in-situ strategy for the construction of high-dispersive cobalt oxide (CoO) nanoneedle arrays, which grow vertically on a copper foam substrate. It is demonstrated that this nanoneedle CoO electrodes provide abundant electrochemical surface area. The resulting CoO arrays directly act as binder-free anodes in lithium-ion batteries with the copper foam functioning as the current collector. The highly-dispersed feature of the nanoneedle arrays enhances the effectiveness of active materials, leading to outstanding rate capability and superior long-term cycling stability. These impressive electrochemical properties are attributed to the highly-dispersed self-standing nanoarrays, the advantages of binder-free constituent, and the high exposed surface area of the copper foam substrate compared to copper foil, which enrich active surface area and facilitate charge transfer. The proposed approach to prepare binder-free lithium-ion battery anodes streamlines the electrode fabrication steps and holds significant promise for the future development of the battery industry.

Freestanding ReS2/Graphene Heterostructures as Binder-Free Anodes for Lithium-Ion Batteries

It is still challenging to develop anode materials with high capacity and long cycling stability for lithium-ion batteries (LIBs). To address such issues, herein, for the first time, we present a three-dimensional and freestanding ReS2/graphene heterostructure (3DRG) as an anode synthesized via a one-pot hydrothermal method. The hybrid shows a hierarchically sandwich-like, nanoporous, and conductive three-dimensional (3D) network constructed by two-dimensional (2D) ReS2/graphene heterostructural nanosheets, which can be directly utilized as a freestanding and binder-free anode for LIBs. When the current density is 100 mA g-1, the 3DRG anode delivers a high reversible specific capacity of 653 mAh g-1. The 3DRG anode also delivers higher rate capability and cycling stability than the bare ReS2 anode. The markedly boosted electrochemical properties derive from the unique nanoarchitecture, which guarantees massive electrochemical active sites, short channels of lithium-ion diffusion, fast electron/ion transportation, and inhibition of the volume change of ReS2 for LIBs.

Preparation of SnO2/TiO2/C composite fibres and their use as binder-free anodes for lithium-ion batteries

Preparation of SnO2/TiO2/C composite fibres and their use as binder-free anodes for lithium-ion batteries

Nickel foam deposited with borophene sheets used as a self-supporting binder-free anode for lithium-ion batteries

Nickel foam-supported borophene sheets were prepared using an improved chemical vapor deposition process. The as-obtained borophene sheets have crystaline nature, where the β12phase is dominant and contributes to high capacity for lithium storage.

Flexible anodic SnO2 nanoporous structures uniformly coated with polyaniline as a binder-free anode for lithium ion batteries

• SnO 2 @PANI anodes were successfully synthesized through wet-chemical approach. • Anodic nanoporous SnO 2 leads to shortened lithium ion diffusion lengths. • Uniformly deposited PANI onto nanoporous SnO 2 serves as an effective buffer layer. • Optimized thickness of PANI layer is controlled by adjusting the scan rate. Herein we report a wet-chemical process to obtain binder-free anodes for lithium-ion batteries (LIBs) using a straightforward and easily scalable approach. Electrochemical deposition, anodization, and electropolymerization are used to firmly attach a nanoporous and flexible SnO 2 film, uniformly coated with polyaniline (PANI), onto a Cu substrate. The three-dimensional, flexible, and nanoporous SnO 2 @PANI electrodes exhibit good specific capacity, capacity retention, and charge transfer resistance. Its favorable electrochemical properties are attributed to the large surface area, high electrical conductivity, and effective reduction of volume expansion. These results demonstrate that the proposed approach to forming SnO 2 @PANI electrodes is a promising strategy for constructing high-performance binder-free anodes for emerging flexible LIBs.

Upcycling of photovoltaic silicon waste into ultrahigh areal-loaded silicon nanowire electrodes through electrothermal shock

Upcycling of photovoltaic silicon (Si) waste to produce high-energy-density energy storage materials represents an effective way to achieve carbon neutrality. However, at present, photovoltaic Si waste (WSi) can only be suitable for degraded utilization because WSi recycling processes are limited by deep oxidation, entrainment of trace impurities, and structural reconstruction difficulties. Here, we propose an electrothermal shock method to convert photovoltaic WSi directly into ultrahigh areal-loaded (4.02 mg cm−2) silicon nanowire (SiNW) electrodes. High-gradient thermal fields (∼104 K s−1) are produced to drive the formation and deposition of gaseous Si molecules using the easy oxidation characteristics of the WSi powder. Carbon fiber cloth is used as both a heater and an in-situ growth substrate for the SiNWs to construct SiNW-carbon cloth self-supporting electrode (SiNWs@CC) structures. When used as a binder-free anode for lithium-ion batteries, it exhibits ultra-high areal capacity (3.2 mAh cm−2 for 600 cycles, capacity retention rate >83%) and long-cycle stability (1706.2 mAh g−1 at 1 A g−1 after 1800 cycles). A full battery assembled using a commercial LiFePO4 cathode also demonstrates stable cycling performance (>91.2% initial capacity maintained at 0.5 C for 250 cycles). Such an upcycling strategy will help to promote environmentally friendly, economical, and sustainable development of the photovoltaic and energy storage industries.

Binder-free nanostructured germanium anode for high resilience lithium-ion battery

The development and the characterization of a nanostructured binder-free anode for lithium-ion batteries exploiting the germanium high theoretical specific capacity (1624 mAh g−1 for Li22Ge5 alloy) is herein presented. This anode secures remarkable performances in different working conditions attaining a 95% capacity retention at 1C (i.e., 1624 mA g−1) after 1600 cycles at room temperature and a specific capacity of 1060 mAh g−1 at 10C and 450 mAh g−1 at 60C. The nanostructured binder-free germanium-based anode shows also strong resilience in terms of temperature tests, being it tested from -30 °C to +60 °C. Indeed, the specific capacity remains unaltered from room temperature up to +60 °C, while at 0 °C the cell is still retaining 85% of its room temperature capacity. In a full-cell configuration with LiFePO4 as cathode, the Ge anode showed a stable specific capacity above 1300 mAh g−1 for 35 cycles at C/10. Concerning the fabrication procedure, a two-step realization process is applied, where a Plasma Enhanced Chemical vapor Deposition (PECVD) is employed to grow a germanium film on a molybdenum substrate followed by hydrofluoric acid (HF) electrochemical etching, the latter having the scope of nanostructuring the Ge film. Finally, compositional, morphological, and electrochemical characterizations are reported to fully investigate the properties of the binder-free nanostructured germanium anode here disclosed.

Self-supporting ZnP2@N, P co-doped carbon nanofibers as high-performance anode material for lithium-ion batteries

Searching for high specific capacity anode materials with an optimized structure to achieve high energy density, long cycling life-span, and high rate performance for lithium-ion batteries (LIBs) is a pressing assignment. Metal phosphides have aroused much attention, however, enormous volume variations, poor electrical conductivity, and aggregation of nanoparticles hamper their practical applications. Herein, ZnP2 nanoparticles grown on N, P co-doped carbon nanofibers (ZnP2 @NPCNFs) composite synthesized by electrospinning and heat treatment is reported to directly act as binder-free anode in LIBs. The 3D self-standing ZnP2 @NPCNFs featuring good flexibility can not only boost conductivity and alleviate the volumetric fluctuations in the cycling course, but also buffer the agglomeration and pulverization of nanoparticles. Lithium storage of ZnP2 @NPCNFs electrode obey the conversion reaction mechanism. Besides, the additional lithium intercalation active sites created by the doped-nitrogen and the existence of PC bond along with the space-confined effect of NPCNFs are conjointly beneficial to endow the ZnP2 @NPCNFs electrode with distinctive electrochemical properties. When assembled as the anode, the ZnP2 @NPCNFs electrode reached a high reversible capacity of 746 mA h g−1 after 100 cycles at 0.2 A g−1 and 406.49 mA h g−1 after 1000 cycles at 2 A g−1. Electrochemical tests manifest that most of the capacity contribution comes from capacitive process. Moreover, the similar superior electrochemical performances are obtained in the LiFePO4//ZnP2 @NPCNFs full cell. Generally, this study widens researchers’ horizons to conceive rational structure of metal phosphides anodes in LIBs with high capacity conservation.

Novel self-supporting multilevel-3D porous NiO nanowires with metal-organic gel coating via “like dissolves like” to trigger high-performance binder-free lithium-ion batteries

In this work, we put forward a concept of novel self-supporting multilevel-3D porous NiO nanowires and successfully synthesize them to be used as binder-free electrode for lithium-ion batteries (LIBs). According to the “like dissolves like” rule, Zr-based metal-organic gel (Zr-MOG) with the same organic ligand of the precursor of NiO is in situ coated on the surface of novel multilevel-3D porous nanowires, which not only effectively stabilizes the multilevel-3D porous network structure, but also adheres the electrode material to the surface of the Cu foil effectively and prevents electrode pulverization or shedding due to its own viscosity without adding binder (PVDF) in the process of fabricating electrode. Contact angle analysis illustrates Zr-MOG possesses potential to provide cementation power. Through theoretical simulation, the binding energy of NiO@Zr-MOG is lower than NiO, demonstrating the superiority to occur the redox reaction. The novel self-supporting multilevel-3D porous NiO nanowires coated by Zr-MOG possess superior electrochemical performance of LIBs (the specific capacity reached 1816.3 mAh g −1 at the current density of 100 mA g −1 , remained at 1318.7 mAh g −1 after 150 cycles). This work will provide a new perspective for the fabrication of high-performance binder-free LIB electrodes. • Put forward the concept of novel multilevel-3D porous nanowires. • Binder-free lithium-ion battery anode by “like dissolves like” coating. • The superiority of NiO@Zr-MOG was demonstrated by theoretical simulation. • The fabrication method is applicable to other transition metal oxides.

Copper oxide@cobalt oxide core–shell nanostructure, as an efficient binder-free anode for lithium-ion batteries

Here, cobalt oxide nanostructures synthesized on vertically aligned copper oxide nanowires (NWs) have been investigated as a possible anode material for Lithium-ion batteries (LIBs). Copper oxide NWs were formed by thermal oxidation of electrochemically deposited copper on the stainless steel mesh substrate. The process used allows the formation of highly dense copper oxide NWs with excellent adhesion to the conductive current collector substrate. A simple hydrothermal method was implemented for the deposition of cobalt oxide nanostructures on the copper oxide NWs. The as-prepared binder-free copper oxide@cobalt oxide NWs electrode exhibits a high initial specific capacity of 460 mAh g−1 at a current density of 148 mA g−1. The fabricated core–shell structure effectively improved the capacity of the fabricated half-cell by four times after 30 cycles, compared with bare copper oxide NWs. In addition to its straightforward and inexpensive synthesis process, the improved electrochemical performance suggests the copper oxide@cobalt oxide NWs electrode as a potential anode material for advanced LIBs.

Ternary Si–SiO–Al Composite Films as High-Performance Anodes for Lithium-Ion Batteries

Silicon (Si) is a promising anode material for lithium-ion batteries but has long been suffering from low conductivity, drastic volume change, poor cycling performance, etc. Adding SiO, Al, etc. to form Si-based binary composite films can improve some properties but have to give up others. Here, we prepared a ternary Si-SiO-Al composite film anode by adding SiO and Al together into Si using magnetron sputtering. This film has an extraordinary combination of conductivity, specific capacity, cycling stability, rate performance, etc., when compared with its binary and unary counterparts. While both SiO and Al can separately mitigate anode cracking resulting from the huge volume expansion during the lithiation/delithiation cycling process, the synergetic effect of adding SiO and Al together to form a ternary composite film can produce much better results. This film maintains an island structure that can efficiently buffer the volume expansion during the cycling process, giving rise to superior cycling performance and excellent rate performance. In addition, the cosputtered Al improves the electrical conductivity of the anode at the same time. This unique combination of anode properties, together with the low cost, suggests that the Si-SiO-Al composite film has the potential to be commercialized as a binder-free anode for lithium-ion batteries. This work also provides an efficient means to modulate the anode properties with more degrees of freedom.

Facile synthesis and simulation of MnO2 nanoflakes on vertically aligned carbon nanotubes, as a high-performance electrode for Li-ion battery and supercapacitor

This study reports the successful fabrication of high-performance flexible binder-free lithium-ion battery anode and supercapacitor based on the synthesis of 3D hierarchical MnO2 nanoflakes (NFs) on vertically aligned carbon nanotubes (VACNTs) grown upon stainless steel (SS). The experimental results revealed that the prepared electrodes were well served as supercapacitors with a tremendous specific capacitance of MnO2 NFs VACNT/SS 1131 F/g at 0.25 A/g in 0.5 mol.L−1 Na2SO4, 518.8% more than VACNT/SS (218 F/g). Compared to other MnO2 NFs/CNT composites, as-fabricated binder-free MnO2 NFs/VACNTs electrode achieves outstanding performance with high initial discharge and charge capacities of 2438 and 1289 mAhg−1 at a current density of 250 mAg−1, respectively. The fabricated anode anode further demonstrates an extraordinarily high reversible capacity of 803.2 mAhg−1 with columbic efficiency of 98.4% at a current density of 250 mAg−1 over 150 charge/discharge runs. Compared to pure VACNTs electrode, the MnO2/VACNTs has significantly improved cycling stability and lithium storage capability, making this nanocomposite a promising anode for LIBs. Meanwhile, the electrochemical behavior of MnO2 NFs/VACNTs anode was evaluated using a numerical simulation approach. The simulation findings results showed excellent consistency between numerical and experimental results.

Synthesis of graphene quantum dots-coated hierarchical CuO microspheres composite for use as binder-free anode for lithium-ion batteries

There is an urgent need to develop improved anode materials for lithium-ion batteries (LIBs). Herein, we report the synthesis of a graphene quantum dots (GQDs)-coated hierarchical nanoflake-based CuO microspheres (H–CuO) composite on Cu foam via a one-pot hydrothermal technique for use as a binder-free anode for LIBs. The carboxyl-functionalized GQD coating on H–CuO not only results in lower charge-transfer resistance and enhanced electrical conductivity but also prevents the dissolution and agglomeration of the electrode. The GQDs/H–CuO composite anode exhibits a reversible capacity as high as 609 mAh g−1 (pristine H–CuO: 61 mAh g−1) after 200 cycles at 0.2 A g−1. It also shows long-term cycling stability, exhibiting a capacity retention rate of 79.4% after 1000 cycles (pristine H–CuO: 0.7%) at a high current density (2 A g−1) and improved initial coulombic efficiency at 88.2% (pristine H–CuO: 75.2%). The superior electrochemical properties of the GQDs/H–CuO composite anode are attributable to the graphene networks, which help maintain a high specific surface area and effectively protect the anodic active material from forming an unstable solid electrolyte interface layer. The proposed strategy for fabricating the GQD-coated metal oxide microsphere-based anode should contribute to the development of next-generation LIBs with improved electrochemical performance.

Pencil lead based low cost and binder-free anode for lithium-ion batteries: effect of different pencil grades on electrochemical performance

We depict a facile and one step approach to fabricate a high capacity anode by drawing pencil lead onto the current collector. For efficient loading and adhesion, stainless steel substrate used as a collector is roughened using sand paper before drawing the pencil lead onto it. As pencil lead comprises graphite-clay (primarily silica) composites, graphite provided cyclic stability due to lithium ion intercalation while SiO2 resulted in higher reversible capacity by facilitating alloying and de-alloying of lithium with silicon. To evaluate their role further onto the anodic performance, three different pencil grades (4H, 4B and 10B) are used which varied in graphite and silica composition. A detailed comparative analysis of their electrochemical performances is done and is further correlated to their structural parameters. Importantly, the fabrication of anode is not only facile but also is solvent and binder free and is also scalable for real application.Graphic Abstract

Hollow multi-nanochannel carbon nanofiber/MoS2 nanoflower composites as binder-free lithium-ion battery anodes with high capacity and ultralong-cycle life at large current density

The electrode materials with high pseudocapacitance can enhance the rate capability and cycling stability of lithium-ion storage devices. Herein, we fabricated MoS2 nanoflowers with ultra-large interlayer spacing on N-doped hollow multi- nanochannel carbon nanofibers (F2-MoS2/NHMCFs) as freestanding binder-free anodes for lithium-ion batteries (LIBs). The ultra-large interlayer spacing (0.78∼1.11 nm) of MoS2 nanoflowers can not only reduce the internal resistance, but also increase accessible active surface area, which ensures the fast Li+ intercalation and deintercalation. The NHMCFs with hollow and multi-nanochannel structure can accommodate the large internal strain and volume change during lithiation/delithiation process, it is beneficial to improving the cycling stability of LIBs. Benefiting from the above combined structure merits, the F2-MoS2/NHMCFs electrodes deliver a high rate capability 832 mA h g−1 at 10 A g−1 and ultralong cycling stability with 99.29 and 91.60 % capacity retention at 10 A g−1 after 1000 and 2000 cycles, respectively. It is one of the largest capacities and best cycling stability at 10 A g−1 ever reported to date, indicating the freestanding F2-MoS2/NHMCFs electrodes have potential applications in high power density LIBs.