Anode For Lithium-ion Batteries Research Articles

Lithiation Depth Regulation of Silicon Anodes toward Excellent Stability.

Silicon (Si) is an appealing choice of anode for next-generation lithium ion batteries with high energy density, but its dramatic volume expansion makes it a tremendous challenge to achieve acceptable stability. Herein, we demonstrate that no capacity decay is observed during the testing period when the lithiation depth of Si nanoparticles is regulated at 2000 mAh g-1 or below, the fracture of Si anode films is well mitigated under suitable regulation of lithiation depth, and the cycled Si remains particulate without turning flocculent as under full lithiation. In addition, the solid electrolyte interphase (SEI) with a LiF-dominated outer region produced under lithiation regulation could better passivate the Si anodes and prevent further electrolyte decomposition than the mosaic-type SEI formed under full lithiation. Regulating lithiation depth proved to be a feasible solution to the pressing volume issues, and optimization of capacity utilization should be considered as much as materials-level optimization.

Densification of Alloying Anodes for High Energy Lithium-Ion Batteries: Critical Perspective on Inter- Versus Intra-Particle Porosity.

High Li-storage-capacity particles such as alloying-based anodes (Si, Sn, Ge, etc.) are core components for next-generation Li-ion batteries (LIBs) but are crippled by their intrinsic volume expansion issues. While pore pre-plantation represents a mainstream solution, seldom do this strategy fully satisfy the requirements in practical LIBs. One prominent issue is that porous particles reduce electrode density and negate volumetric performance (WhL-1) despite aggressive electrode densification strategies. Moreover, the additional liquid electrolyte dosage resulting from porosity increase is rarely noticed, which has a significant negative impact on cell gravimetric energy density (Whkg-1). Here, the concept of judicious porosity control is introduced to recalibrate existing particle design principles in order to concurrently boost gravimetric and volumetric performance, while also maintaining the battery's cycle life. The critical is emphasized but often neglected role that intraparticle pores play in dictating battery performance, and also highlight the superiority of closed pores over the open pores that are more commonly referred to in the literature. While the analysis and case studies focus on silicon-carbon composites, the overall conclusions apply to the broad class of alloying anode chemistries.

High-stable and High-capacity Sn/SnO2@C as Anode of Lithium-ion Batteries

High-stable and High-capacity Sn/SnO2@C as Anode of Lithium-ion Batteries

Binder-dependent electrochemical properties of high entropy oxide anodes for lithium-ion batteries

High entropy oxide (HEO) materials have recently emerged as promising anodes for lithium-ion batteries (LIBs). In this study, we conduct the first comparative analysis to investigate the influence of various electrode binders on electrochemical properties of (CrMnFeNiCu)3O4 HEO anodes. The organic-solvent-soluble polyvinylidene fluoride and water-soluble polyvinyl formamide, sodium carboxymethyl cellulose, sodium alginate, and sodium polyacrylate (NaPAA) binders are examined. Notably, the NaPAA binder leads to a significant enhancement in the HEO performance. The NaPAA coating on (CrMnFeNiCu)3O4 effectively improves the electrode charge-discharge Coulombic efficiency and mitigates the electrode deterioration. Binder adhesion strength and stability toward electrolyte are assessed. The charge-transfer resistance and apparent Li+ diffusion of the HEO electrodes with various binders, accompanied by the post-cycling analyses, are examined. By employing the NaPAA binder, exceptional electrode capacities of 800 and 495 mAh g–1 are attained at charge-discharge rates of 50 and 2000 mA g–1, respectively, without noticeable capacity degradation after 300 cycles. The thermal reactivity of the lithiated electrodes is investigated using differential scanning calorimetry, and the impact of binders on the electrode exothermic onset temperature and total heat released is studied. Our findings provide valuable insights for enhancing the performance and safety of HEO anodes for LIBs.

Polymer-Supported Graphene Sheet as a Vertically Conductive Anode of Lithium-Ion Battery.

The increasing demand for electric vehicles necessitates the development of cost-effective, mass-producible, long-lasting, and highly conductive batteries. Making this kind of battery is exceedingly tricky. This study introduces an innovative fabrication technique utilizing a laser-induced graphene (LIG) approach on commercial Kapton film to create hexagonal pores. These pores form vertical conduction paths for electron and ion transportation during lithiation and delithiation, significantly enhancing conductivity. The nongraphitized portion of the Kapton film makes it a binder-less, free-standing electrode, providing mechanical stability. Various analytical techniques, including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Raman spectroscopy, and atomic force microscopy (AFM) are utilized to confirm the transformation of a 3D porous graphene sheet from a commercial Kapton film. Cross-sectional SEM images verify the vertical connections. The specific capacity of 581 mAh g-1 is maintained until the end, with 99% coulombic efficiency at 0.1C. This simple manufacturing method paves the pathway for future LIG-based, cost-effective, lightweight, mass-producible, long-lasting, vertically conductive electrodes for lithium-ion batteries.

Interconnected Multifunctional Waterborne Polyurethane Binder for Structural Robustness of Si Anodes in Lithium-Ion Batteries

Interconnected Multifunctional Waterborne Polyurethane Binder for Structural Robustness of Si Anodes in Lithium-Ion Batteries

ZIF-derived "cocoon"-like in-situ Zn/N-doped carbon as high-capacity anodes for Li/Na-ion batteries

Owing to the unique structure and physicochemical properties, including high specific surface area, self-doped N atoms, open pore structure and good chemical stability, zeolitic imidazolate frameworks (ZIFs) and their derivatives have been widely used in the field of energy storage. Here, a new type of "cocoon"-like Zn/N doped ZIF-derived porous carbon (Zn@N-C-800) is synthesized as an anode for lithium-ion batteries (LIBs) and sodium ion batteries (SIBs) through a one-step carbonization process using a novel Zn-ZIF as the precursor. In Zn@N-C-800, the "cocoon"-like disordered carbon skeleton is conducive to electrolyte infiltration, while the Zn/N doping can provide additional active sites for ion storage. Benefiting from these unique structural characteristics, Zn@N-C-800 achieves excellent electrochemical performances as anode for both LIBs and SIBs: an ultrahigh rate capability of 352 mAh g-1 can be delivered at 12.8Ag-1 for LIBs; an outstanding long-term cycling stability (312 mAh g-1 at 1Ag-1 after 2000 cycles) can be achieved for SIBs. This paper provides new ideas for the design and preparation of high-performance anodes for LIBs and SIBs.

Rigid-flexible mediated Co-polyimide enabling stable silicon anode in lithium-ion batteries

Silicon is considered as a promising electrode materials for the next generation of lithium-ion batteries. However, it’s commercial applications are hindered by significant volume changes. In this study, copolyimide binders with adjustable rigidity and flexibility were synthesized through simple copolymerization. The rigid segments containing adenine groups (p-APA) provide excellent mechanical strength and interface interaction, while flexible segments containing siloxane bonds and alkane chains (DS-NH2) can buffer volume changes through enhanced mobility and topological entanglement of molecular segments. Optimizing the copolymerization ratio helps minimize damage to the silicon electrode structure and stabilizes solid electrolyte interphase (SEI) growth. Compared to the rigid polyimide binders, rigid-flexible coupling strategy improves cycling stability, remaining a capacity of 2170 mAh/g at 2 A/g after 200 cycles and exhibiting stable cycling for over 750 cycles with a capacity limitation of 1500 mAh/g. The high mass loading silicon anodes, micron-sized silicon oxide electrodes and the full cells also exhibit favorable electrochemical performance. This research provides valuable insights for designing high-performance aromatic polymer binders for high energy density lithium-ion batteries.

Enabling stable high lithium storage of Si anode via synergistic effects of nanosized Fe3C and partially graphitized porous carbon

Si is considered as a promising anode for high-energy lithium-ion batteries (LIBs) because of its ultrahigh theoretical specific capacity and desired working potential. However, the main problems of Si as an anode are still faced with low conductivity and inevitable structure damage caused by large volume change during cycle. Although design of Si/C composites effectively mitigates the above problems, their preparation usually involves complex methods. This work demonstrates a very simple ball milling and subsequent carbonization approach for the preparation of high-performance Si NPs@Fe3C@PC anode, which integrates partially hollow Fe3C nanoparticles (Fe3C) and partially graphitized porous carbon (PC) into Si nanoparticles (Si NPs)-based composite. It is found that Fe3C with catalysis is favorable not only to formation of a graphitized porous carbon during material preparation but also to formation of a stable solid electrolyte interfaces (SEI) on electrode surface during cycle. With Fe3C, the Si NPs@Fe3C@PC shows smaller Li+ adsorption energy, lower activation energy, higher electric conductivity, larger Li+ diffusion coefficient and a thinner SEI film than Si NPs and Si NPs@PC counterparts. The findings verify that the synergistic effects of the Fe3C and PC provide fast kinetics, high capacitive contribution, improved structure stability and a stable LiF-rich SEI film for Si NPs@Fe3C@PC during cycle. Therefore, Si NPs@Fe3C@PC shows excellent electrochemical performance, gaining 1786, 1211.4 and 411.5 mAh/g after 210, 650 and 840 cycles at 100, 1000 and 5000 mA g−1, respectively. Finally, this contribution proposes a simple and effective strategy for improving Si NPs performance and hence obtaining a high-performance of Si-based anode for LIBs.

Dynamic Magnesiothermic Reduction of Various Silica to Porous Silicon Structures for Lithium Battery Anodes

A dynamic magnesiothermic reduction (DMR) of various silica having different size and porosity is conducted to study the effects of silica properties on the ⅰ) DMR reaction kinetics, ⅱ) properties of resulting pSi microparticles, and ⅲ) performances of pSi/C composites as anodes in lithium batteries. A DMR kinetic study using the Ginstling–Brounstein diffusion model shows that the smaller the silica particle size, the larger the reduction rate and the lower the apparent activation energy. Irrespective of silica properties, all the resulting pSi particles have mesoporous structures. The pSi particles comprise interconnected small primary silicon nanoparticles (approximately 30–40 nm in diameter) to render similar particle morphologies to those of parent silica. Owing to these appealing features of pSi particles, pSi/C composites exhibit excellent cycling performance up to over 200 cycles and high rate capabilities, whereas SiMP/C (prepared with a non-porous silicon microparticles) lose most of its capacity in early cycles owing to high resistance build-up during cycling. Overall, the DMR of silica precursors of several micrometers or less in size (preferentially porous precursors) are desirable for the production of high-purity pSi microparticles for use in high-capacity and stable anodes for advanced lithium batteries.

Cost-effective preparation of high-performance Si@C anode for lithium-ion batteries

Cost-effective preparation of high-performance Si@C anode for lithium-ion batteries

Ice template-induced assembly coupled with carbonization strategy for preparation of sulfur-doped porous carbon nanosheets from lignite as high-capacity anode for lithium-ion batteries

Two-dimensional (2D) porous carbon nanosheets with heteroatom doping are promising anode materials for lithium-ion batteries (LIBs) due to their distinctive sheet-like structure and excellent electrical conductivity. Limited by high preparation costs and cumbersome preparation processes, the large-scale production of carbon nanosheets remains a major challenge. Herein, a series of sulfur-doped porous carbon nanosheets (SCNSs) are successfully synthesized through ice template-induced assembly coupled with a carbonization approach using aromatic ring fragments exfoliating from lignite as the precursor and K2SO4 as the sulfur source. The prepared SCNSs exhibit well-defined sheet-like structures, abundant hierarchical nanopores, large specific surface areas (∼1761 m2·g−1), and high sulfur doping contents (∼7.72 at%). Such unique microstructure characteristics of SCNSs not only provide favorable and efficient channels for the lithium-ions/electrons transportation but also offer sufficient available space or active sites for lithium-ions storage. When used as anode materials for LIBs, the SCNS-3 shows high reversible capacity (1620 mAh·g−1 at 0.05 A·g−1), excellent rate performance (315 mAh·g−1 at 2 A·g−1), and superior cycling stability (901 mAh·g−1 at 1 A·g−1 after 500 cycles). Lithium storage behavior analysis indicated that the capacitance enhancement in SCNSs anodes is primarily due to improved capacitive behavior. This study provides a novel and effective route for the large-scale production of sulfur-doped carbon nanosheets using aromatic ring fragments exfoliated from lignite, which demonstrates promising industrial application potential in LIBs anode materials.

A gradient-distributed binder with high energy dissipation for stable silicon anode

Silicon is considered as a promising alternative to traditional graphite anode for lithium-ion batteries. Due to the dramatic volume expansion of silicon anode generated from the insertion of Li+ ions, the binder which can suppress the severe volume change and repeated massive stress impact during cycling is required greatly. Herein, we design a gradient-distributed two-component binder (GE-PAA) to achieve excellent cyclic stability, and reveal the mechanism of high energy dissipative binder stabilized silicon electrodes. The inner layer of the electrode is the polyacrylic acid polymer (PAA) with high Young’s modulus, which is used as the skeleton binder to stabilize the silicon particle interface and the electrode structure. The outer layer is the gel electrolyte polymer (GE) with lower Young’s modulus, which releases the stress generated during the lithiation and de-lithiation process effectively, achieving the high structural stability at the molecular level and silicon particles. Due to the synergistic effect of the gradient binder design, the silicon electrode retains a reversible capacity of 1557.4 mAh g-1 after 200 cycles at the current density of 0.5 C and 1539.2 mAh g-1 at a high rate of 1.8 C. This work provides a novel binder design strategy for Si anode with long cycle stability.

Regeneration of photovoltaic industry silicon waste toward high-performance lithium-ion battery anode

Regeneration of photovoltaic industry silicon waste toward high-performance lithium-ion battery anode

Monolithic Layered Silicon Composed of a Crystalline-Amorphous Network for Sustainable Lithium-Ion Battery Anodes.

While nanostructural engineering holds promise for improving the stability of high-capacity silicon (Si) anodes in lithium-ion batteries (LIBs), challenges like complex synthesis and the high cost of nano-Si impede its commercial application. In this study, we present a local reduction technique to synthesize micron-scale monolithic layered Si (10-20 μm) with a high tap density of 0.9-1.0 g cm-3 from cost-effective montmorillonite, a natural layered silicate mineral. The created mesoporous structure within each layer, combined with the void spaces between interlayers, effectively mitigates both lateral and vertical expansion throughout repeated lithiation/delithiation cycles. Furthermore, the remaining SiO2 network fortifies the layered structure, preventing it from collapsing during cycling. Half-cell tests reveal a capacity retention of 92% with a reversible capacity of 1130 mAh g-1 over 500 cycles. Moreover, the pouch cell integrated with this Si anode (with a mass loading of 3.0 mg cm-2) and a commercial NCM811 cathode delivers a high energy density of 655 Wh kg-1 (based on the total mass of the cathode and anode) and maintains 82% capacity after 200 cycles. This work demonstrates a cost-efficient and scalable strategy to manufacture high-performance micron Si anodes for the ever-growing demand for high-energy LIBs.

Facile synthesis of SiOx/C as high-performance anodes for lithium-ion batteries

Despite its high capacity (∼2615 mAh·g−1), silicon oxide (SiOx) suffers from low electrical conductivity and volume expansion during cycling, leading to capacity fading. In this work, a SiOx/C composite was synthesized by magnesium thermal reduction using co-assembled mesoporous SiO2 and graphitic carbon nitride (g-C3N4) as precursors. The SiOx/C composite displays a sheet-like nanostructure with highly dispersed SiOx. The presence of carbon enhances the conductivity and structural stability of the composite, leading to a low charge resistance (94.0 Ω), fast lithium diffusion (DLi+ = 5.15 × 10−14 cm2·s−1), and excellent cycling capability (863 mAh·g−1 after 160 cycles).

Construction of sub micro-nano-structured silicon based anode for lithium-ion batteries

The significant volume change experienced by silicon (Si) anodes during lithiation/delithiation cycles often triggers mechanical-electrochemical failures, undermining their utility in high-energy-density lithium-ion batteries (LIBs). Herein, we propose a sub micro-nano-structured Si based material to address the persistent challenge of mechanic-electrochemical coupling issue during cycling. The mesoporous Si-based composite submicrospheres (M-Si/SiO2/CS) with a high Si/SiO2 content of 84.6 wt.% is prepared by magnesiothermic reduction of mesoporous SiO2 submicrospheres followed by carbon coating process. M-Si/SiO2/CS anode can maintain a high specific capacity of 740 mAh g−1 at 0.5 A g−1 after 100 cycles with a lower electrode thickness swelling rate of 63%, and exhibits a good long-term cycling stability of 570 mAh g−1 at 1 A g−1 after 250 cycles. This remarkable Li-storage performance can be attributed to the synergistic effects of the hierarchical structure and SiO2 frameworks. The spherical structure mitigates stress/strain caused by the lithiation/delithiation, while the internal mesopores provide buffer space for Si expansion and obviously shorten the diffusion path for electrolyte/ions. Additionally, the amorphous SiO2 matrix not only servers as support for structure stability, but also facilitates the rapid formation of a stable solid electrolyte interphase layer. This unique architecture offers a potential model for designing high-performance Si-based anode for LIBs.

Insight into the Role of Fluoroethylene Carbonate in Solid Electrolyte Interphase Construction for Graphite Anodes of Lithium-Ion Batteries

Insight into the Role of Fluoroethylene Carbonate in Solid Electrolyte Interphase Construction for Graphite Anodes of Lithium-Ion Batteries

A Facile Chemical Reduction Approach of Li–Sn Modified Li Anode for Dendrite Suppression

Lithium dendrites are among the most significant threats associated with the practical application of lithium metal anode in lithium batteries. Lithium dendrites are caused by the slow Li‐ion diffusivity in the bulk lithium, which results in a non‐uniform electric field‐cum‐uneven Li plating/stripping at the electrode/electrolyte interface over prolonged cycling. Herein, a facile chemical reduction method is utilized to construct a Li‐ion diffusive Li–Sn protective layer on the electrolyte‐exposed surface of lithium metal to overcome the aforementioned challenge. A systematic study on the SnCl4 precursor concentration variation demonstrated that 25 mM SnCl4 concentration is the most effective and displays a cumulative areal capacity beyond 700 mAh cm−2 at 1 mA cm−2 for 1 h. Moreover, it exhibits superior cumulative capacities than bare Li metal at higher current densities of 2 and 3 mA cm−2. In situ optical microscopy reveals more uniform lithium deposition on the Li–Sn‐modified electrode, while mossy and dendritic lithium growth is observed on the bare lithium electrode. Full cells fabricated with Li–Sn modified anode and NMC532 cathode exhibited 83% capacity retention after 150 cycles, outperforming bare Li‐containing cells, which shows a catastrophic decay post 100 cycles, illustrating the propensity for safer Li metal batteries with Li–Sn modified anode.

Core-shell NiCo2S4@C with three dimensional carbon frameworks for enhanced asymmetrical supercapacitor and lithium storage performance

Transition-metal sulfides have been considered as promising candidates for electrochemical supercapacitor and lithium ion batteries. Unfortunately, the shortcomings including large volume change, low conductivity as well as severe structural exfoliation from conductive substrate or current collector inhibit their practical application. Herein, the hydrothermal and solvothermal approach are developed for the controllable synthesis of core-shell NiCo2S4@C with three dimensional carbon frameworks. As an asymmetric supercapacitor, the NiCo2S4@C/YP-50 F displays a high energy density of 46.7 Wh kg−1 at a power density of 0.8 kW kg−1 and the good cycling stability (∼110 % of the initial capacitance retention at 16 kW kg−1 over 2000 cycles). Furthermore, the NiCo2S4@C exhibits the specific capacity of 414 mAh g−1 after 500 cycles at 2000 mA g−1 when evaluated as anode for lithium ion batteries. The excellent performance can be ascribed to the core-shell structure and the three dimensional carbon frameworks. The synthetic approach can be extended to fabricate other high performance metal sulfides for energy storage.