Generation Lithium-ion Batteries Research Articles

Understanding Diffusion and Electrochemical Reduction of Li+ Ions in Liquid Lithium Metal Batteries

Lithium metal has drawn significant interest as an anode material for next generation lithium (Li) batteries. However, due to its propensity to form dendrites in commonly used electrolytes during repeated cycling, it has not yet been commercialized in secondary batteries. The formation of a Li protrusion is determined by the relative speed of Li+ ions being reduced and how fast they can be replenished in the vincinity of electrode. However, it is very difficult to quantify such kinetic parameters of Li+ ion in different electrolytes, not mentioning the identification of the desired electrolyte recipe to mitigate Li dendrite formation. Herein, we use microelectrodes to study the growth mechanism of electroplated Li by measuring the Li+ diffusion coefficient (DLi) and exchange current density (io) in different electrolytes. The different Li morphologies formed on microelectrodes are well correlated to their diffusion rate and electrochemical reduction speed on the electrode, providing a fast electrochemical tool to screen compatible electrolytes for Li metal batteries.

Assessing Electrochemical Stability Windows of Li1+XAlxM2-X(PO4)3 (M=Ge,Ti) Nasicon Solid Electrolytes for Their Application in All Solid-State Lithium Batteries

All-Solid-State Lithium Batteries (ASSLBs) are a new generation of lithium batteries that are developed to meet expectations in terms of safety, stability and high energy density. The liquid electrolyte of conventional Li-ion batteries is replaced in ASSLBs by a safer and more stable solid electrolyte (SE). ASSLBs are promising because they may enable the use of high potential materials as positive electrode and lithium metal as negative electrode. This is only possible through SE stated large electrochemical stability windows (ESW). Nevertheless, values for these electrochemical windows are very divergent in the published literature. Recently, several studies have come to specifically decry the frequent overestimation of SE electrochemical stability windows 1- 4 . Establishing a robust procedure to accurately determine SEs ESW has therefore become crucial.Our work is focused on using an original experimental set up to assess the ESW of two widely investigated NASICON-type SEs Li1.3Al0.3Ti1.7(PO4)3 (LATP) and Li1.5Al0.5Ge1.5(PO4)3 (LAGP). The experimental set-up provides a large contact surface between the SE and the conductive material, which maximizes the redox current signals. A combination of Potentiostatic Intermittent Titration Technique (PITT) and Electrochemical Impedance Spectroscopy (EIS) measurements allowed us to precisely determine the ESW of LATP and LAGP solid electrolytes. Using EIS and physico-chemical characterizations, we attempted to shed light on the degradation mechanisms occurring upon the solid electrolytes’ oxidation. 1 - Y. Tian et al. Energy Environ. Sci. 2017, 10, 1150. 2 - Z. Zhang et al. Energy Environ. Sci. 2018, 11, 1945-1976. 3 - F. Han et al. Adv. Energy Mater. 2016, 6(8), 1501590. 4 - T. Schwietert et al. Nature Mat. 2020, 19, 428–435.

A Simplified Model to Track Si Degradation in Various Systems

Silicon (Si) is considered one of the most promising anode materials for next generation lithium-ion batteries (LIBs), due to the extremely high specific capacity (3580mAh/g). However, it is challenging to use Si anodes for LIBs, because of the large volumetric changes and phase evaluation associated with lithiation/delithiation of Si. These intrinsic issues of Si lead to the rapid degradation in capacity during cycling, especially in full cells assembled with commercial lithium-ion battery cathodes. Efforts have been made in order to stabilize the Si anodes including developing new electrolytes to increase the surface stability, inventing new binders to enhance the mechanical integrity, and using nanoarchitecture to reduce mechanical failures. Leveraging the previous research, this work introduces a simple and effective method to fast identify the failure mechanism for Si anodes and decouple the impacts of surface instability and lithium trapping on the electrochemical behavior. Here, we will apply our model for various systems of Si half cells to discuss the effectiveness of adding the fluorinated electrolyte additive and the use of nanoparticles. Moreover, we will study the effects of surface modification via atomic/molecular layer deposition on the electrochemistry of Si anodes by using our developed method and provide the insights in designing the highly reversible Si anodes. In this study, we will investigate how these aforementioned factors may affect the stability of Si particles as well as the cycle performances. Assisted with electrochemical impedance spectroscopy (EIS), we will keep track with the SEI evolution on Si anode and connect with the capacity degradation in order to explain the importance of interface stability.

Garnet Nb-Doped Li7La3Zr2O12 Ceramic Electrolyte and Its Composite Electrolyte for Solid-State Lithium Batteries

Lithium ion batteries (LIBs) have world-widely emerged as energy storage devices for electronic products, electric vehicles, energy storage systems and special purpose devices. LIBs are increasingly expected to be provided with a shorter battery charging time, a longer battery life and the better battery security for industrial development and social demand. However, most conventional LIBs with active organic liquid electrolytes have suffered from several issues, especially high safety risk and low energy density. Therefore, continuously improving conventional LIBs and designing new-type lithium batteries are extremely urgent. Solid-state lithium batteries (SSLBs) are recognized as the promising candidates of next generation lithium batteries with good safety and high energy density. Solid-state electrolytes (SSEs) as the most critical component in SSLBs largely lead the future battery development. To obtain the SSEs with good overall performance is a prerequisite to realize the potential of SSLBs. Garnet Li7La3Zr2O12 (LLZO) ceramic SSEs have the great potential for SSLBs, owing to high ionic conductivity, wide stable potential window and good electrochemical stability against lithium metal. However, so far, LLZO ceramic SSEs still suffer from critical issues of poor air stability and hard machinability, greatly limiting their practical application. Hence, in this work, the cubic garnet Nb-doped LLZO, Li6.5La3Zr1.5Nb0.5O12, ceramic electrolyte is synthesized by a simple sol-gel process. Stability and mechanical properties of as-synthesized Li6.5La3Zr1.5Nb0.5O12 ceramics are explored in detail. Directly polishing and assembling Li6.5La3Zr1.5Nb0.5O12 ceramic pellets in analog batteries are applied to investigate electrochemical behaviours. In addition, the flexible composite membrane composed of Li6.5La3Zr1.5Nb0.5O12 particles and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer matrix is successfully prepared through tape casting method. The composite membrane shows good machinability. When the composite membrane as electrolyte is applied in the lithium metal cell, good electrochemical performances are exhibited. The composite membrane integrating hard inorganic Li6.5La3Zr1.5Nb0.5O12 ceramics with soft polymer achieves a gain effect of “1+1 > 2”. This work may be helpful for next forward-looking studies of garnet LLZO family SSEs and their extensions.

Strain gradient enhanced chemo-mechanical modeling of fracture in cathode materials for lithium-ion batteries

Next generation lithium-ion batteries (LIBs) cathodes are composed of polycrystalline microstructures where spatial heterogeneity such as grain size is often comparable to the geometric dimension of the cathodes. Incorporating the influence of the aforementioned heterogeneity in a chemo-mechanical continuum description is necessary to address the diffusion induced stress field during electrochemical cycling. Therefore, in the present study, the micro-structural size-dependent characteristic length of the cathode is embedded through a non-classical continuum mechanics approach known as the strain gradient elasticity (SGE) theory. Accordingly, a thermodynamically consistent multi-physics framework is developed where nonlinear diffusion kinetics is included along with the energetic interaction between the lithium-ions and host lattice of the electrode. The coupled governing equations are derived for the spherical cathode, and the generalized differential quadrature (GDQ) method is utilized to build the numerical procedure. The role of material heterogeneity length scale is addressed for strongly coupled chemo-mechanical process. Subsequently, the growth of potential surface flaws is examined under multiple length scales, particle size, and charge rate conditions. Ultimately, a comprehensive fracture map is established to illustrate the regime of flaw insensitivity, partial breakage and complete disintegration. Thus, the present findings can provide a suitable design perspective for fail-safe particulate type composite cathodes.

A universal etching method for synthesizing high-performance single crystal cathode materials

LiNixMnyCo1-x-yO2 (NMC) is considered the most appealing cathode material due to its high energy density and low cost. However, the stability and safety concerns, caused by the degradation of polycrystalline cathode materials during cycling, have restricted their practical applications. To overcome this shortcoming, converting polycrystalline cathode to high-performance single-crystal cathode materials becomes an appealing solution. Here, a universal etching approach is firstly developed to synthesize single-crystal cathode materials. The rate performance of the obtained single-crystal NMC111 is 10–15% more than that of polycrystalline NMC111 whereas the capacity retention of single-crystal NMC111 is enhanced by ~12% after 300 cycles at 0.5C. The obtained single-crystal NMC622 exhibits a pronounced improvement in rate performance, especially at high rates (~28.6% better at 5C and ~129% better at 10C) and has a comparable cycle performance compared to polycrystalline NMC622. Altogether, the findings propose an alternative approach to generate single-crystal particles with high energy density and cycle stability for the next generation lithium-ion batteries.

Spherical Li1.26Fe0.22Mn0.52O2 cathode material assembled by molten salt – Spray granulation method and improved cycling performance for Li-ion batteries

Due to the abundant reserves of Fe and Mn, the Fe–Mn based cathode material have attracted much attention as electrode materials for next generation lithium ion batteries. In order to keep the high activity and improve the stability of the nanoparticles, the spherical Li1.26Fe0.22Mn0.52O2 is assembled by spray granulation method with nano-precursor prepared by molten salt method. The granulated spheres have a higher specific discharge capacity 197 ​mAh g−1 at 0.2C than that of nanoparticles obtained by simple molten salt method. The granulated spheres also exhibit a distinctly improved cycle stability and rate performance. Moreover, the tap density of granulated spheres increases and their specific surface area decreases obviously, indicating that the primary particles contact closely and particle's contact area with electrolyte reduces. Therefore, particle granulation avails to balance material's activity and stability. In addition, the micron-spherical particles are beneficial to make electrode fabrication easier and increase the specific energy density of batteries.

Effects of Plasticizer Content and Ceramic Addition on Electrochemical Properties of Cross-Linked Polymer Electrolyte

The development of a safe electrolyte is the key to improving energy density for next generation lithium batteries. In this work, UV-crosslinked poly(ethylene oxide) (PEO) -based polymer and composite electrolytes are systematically investigated on their ionic conductivity, mechanical and electrochemical properties. The polymer electrolytes are plasticized with non-flammable linear short-chain PEO. In the composite electrolytes, a doped lithium aluminum titanium phosphate (LATP) ceramic, LICGC™, is used as the ceramic filler. It is found that the addition of the plasticizer leads to a tradeoff between ion transport and mechanical properties. In contrast, the addition of ceramic fillers improves both the ionic conductivity and mechanical properties. The sample with 20 wt% of LICGC™ shows a conductivity of ∼0.6 mS cm−1 at 50 °C. This sample also demonstrates much longer cycle life than the neat polymer electrolyte in Li platting/stripping test with a capacity of 1 mAh cm−2. A full cell made with this composite electrolyte against Li metal anode and high voltage LiNi0.6Mn0.2Co0.2O2 cathode shows 94% capacity retention after 30 cycles, compared to 58% capacity retention with the neat polymer electrolyte. These results demonstrate that a hybrid of polymer/ceramic/non-flammable plasticizer is a promising path to high energy density, high voltage lithium batteries.

All-dry synthesis of self-supporting thin Li10GeP2S12 membrane and interface engineering for solid state lithium metal batteries

• All-dry synthesis of thin (~100 μm) sulfide electrolyte. • High room-temperature ionic conductivity (3.6 × 10 -4 S cm −1 ). • Excellent interface stability by an in-situ polymer interlayer. • Outstanding cell performance of as-prepared composite LGPS electrolyte. Sulfide solid electrolytes have attracted much attention for next generation lithium batteries due to their high ionic conductivity and low grain boundary impedance. However, they generally suffer poor processability into a thin membrane applied in high energy–density batteries and usually unstable with some organic solvents and moistures. Furthermore, the huge interfacial resistance, originated from the side reactions at electrode/electrolyte interfaces, deteriorates the electrochemical performance of batteries. Here, we develop a thin (~100 μm) Li 10 GeP 2 S 12 (LGPS) membrane composed by trace polytetrafluoroethylene (PTFE) binder with LGPS powders through all-dry grinding method and reinforced with a nylon mesh. Thin LGPS can not only reduce the cost, but also improve the energy density of the battery. Moreover, the interface stability between the LGPS electrolyte and electrodes has been significantly enhanced by employing an in-situ gel polymerized electrolyte (GPE) on lithium metal anode, and coating LiNbO 3 on LiNi 0.5 Mn 0.3 Co 0.2 O 2 (LNO@NCM532) separately. As a result, the prepared LNO@NCM532|C-LGPS|GPE|Li batteries reveal satisfying discharge specific capacities and good cyclic stabilities at room temperature.

Spindle MnCO3 tightly encapsulated by MXene nanoflakes with strengthened interface effect for lithium-ion battery

The quality of the interface of the MnCO3-based composite electrode materials determines the application of these high-capacity anodes with abundant raw materials, non-toxic, and high thermal stability in the next generation of lithium-ion batteries. In this work, by strengthening the interface effect of composite materials, MXene encapsulated MnCO3 with spindle morphology is designed via a simple and universal two-step process involving hydrothermal synthesis and sonicated assembly in order to overcome the low conductivity and the volume change during charging and discharging of MnCO3. Spindle MnCO3 is formed using excessive salicylic acid (SA) as reducing agent, and encapsulated with MXene through hydrogen bonds. The MXene as a coating layer effectively inhibits the volume expansion of MnCO3 during charging and discharging depending on its flexible mechanical property, and improves the capacitance storage of MnCO3 due to its high electronic conductivity and fast Li+ transport capability. Therefore, MnCO3@MXene as a lithium-ion battery anode improves cycling capabilities with the capacity retention ratio of 91.2% at 5 A g−1 after 2000 cycles. The strategy of preparing MnCO3 and MXene composite materials through self-assembly of hydrogen bonds to enhance the interface effect has a good application prospect in the design of energy storage materials.

UV-ozone contributions towards facile self-assembly and high performance of silicon-carbon fiber materials as lithium-ion battery anodes

Si-carbon composites have been considered as next generation lithium-ion battery anodes, with a view to sufficiently exerting the respective superiorities of high specific capacity of Si as well as excellent mechanical flexibility and electrical conductivity of carbon. However, direct blending of carbon with Si cannot obtain a synergy composite, resulting in inferior cycle properties during charge–discharge due to huge volume changes and deficient electron-conducting channels from the unavoidably aggregated Si. Herein, the composition of carbon fibers (CNFs) with Si nanoparticles (SiNPs) has been performed through UV-ozone surface modification followed by electrostatic self-assembly. It is found that solvent-free UV-ozone exposure of CNFs for 20 min successfully introduces carboxylic groups, as conventional acid treatment for 12 h. Besides UV-ozone surface modification provides an efficient and scalable route, the distribution and functionalization of CNFs can be also modified to effectively combine with amino-functionalized SiNPs. As a result, such Si-CNF composites containing 70.0 wt% SiNPs are able to exhibit excellent cycle performance with high coulombic efficiency of 74.8% at the 1st cycle and high specific discharge capacity of 1063 mAh g−1 at the 400th cycle.

Solvents adjusted pure phase CoCO3 as anodes for high cycle stability

CoCO3 with high theoretical capacity has been considered as a candidate anode for the next generation of lithium-ion batteries (LIBs). However, the electrochemical performance of CoCO3 itself, especially the cyclic stability at high current density, hinders its application. Herein, pure phase CoCO3 particles with different particle and pore sizes were prepared by adjusting the solvents (diethylene glycol, ethylene glycol, and deionized water). Among them, CoCO3 synthesized with diethylene glycol (DG-CC) as the solvent shows the best electrochemical performance owing to the smaller particle size and abundant mesoporous structure to maintain robust structural stability. A high specific capacity of 690.7 mAh/g after 1000 cycles was achieved, and an excellent capacity retention was presented. The capacity was contributed by diverse electrochemical reactions and the impedance of DG-CC under different cycles was further compared. Those results provide an important reference for the structural design and stable cycle performance of pure CoCO3.

Layered MNb3O8 (M=H, Li, Na, K) driven by intercalation pseudo-capacitor for lithium battery anode material

Niobium-based materials have always been regarded as outstanding anode materials due to its capability of multiple electron transfer. Here, layered polyniobate MNb3O8 (M=H, Li, Na) was prepared by ion-exchange of precursors KNb3O8. HNb3O8 present an excellent charge/discharge capacity of 394.1 mAh g−1/426.8 mAh g−1 at 0.1 C and the Coulombic efficiency is 91.99% after fifth cycle. Even after 60 cycles, it still retains substantial discharge specific capacities of 148.7 mAh g−1 at 0.5 C. In addition, by employing technics including XRD, Raman and XPS, HNb3O8 are demonstrated to possess a larger interlayer channel of 1.11 nm and a stronger binding energy to foreign electrons than MNb3O8 (M=K, Li, Na). This properties could justify the best electrochemical performance of HNb3O8. EIS analysis also reveal that HNb3O8 has the smallest charge transfer impedance among all the samples. All these advantages suggest that HNb3O8 can be an alternative anode material for next generation lithium-ion batteries (LIBs).

Uncertainty Quantification Analysis on Mechanical Properties of the Structured Silicon Anode via Surrogate Models

Silicon anode is the most promising candidate for next generation lithium ion batteries. A major drawback limiting its application is the significant volume change during lithiation-delithiation process, which may cause material pulverization and capacity degradation. A novel 3D bi-continuous nanoporous structured Si anode, consisting of porous metal scaffolds and thin Si coating layers, was proven to be an effective method to tackle this issue; however, uncertainty and non-uniformity, inherited from the fabrication process, will be inevitably introduced as important considerations for the performances of the Si anode. In this paper, uncertainty quantification (UQ) analysis is performed on the structured Si anode system to evaluate the influences of various design variables on its performances and to find the design optimization strategy. The biggest hurdle in the UQ study is the computational cost; to mitigate this challenge, a Gaussian Process based surrogate model is constructed using finite element simulation results as training data. It is found that the performances of the anode are rather sensitive to the geometric parameters, i.e. scaffold non-uniformity and Si layer thickness, whereas the mechanical properties of the materials are relatively less important. Furthermore, the optimal design is proposed to minimize the stress concentration in the Si anode.

Ordered mesoporous carbon with tubular framework supported SnO2 nanoparticles intertwined in MoS2 nanosheets as an anode for advanced lithium-ion batteries with outstanding performances

A new nanocomposite based on three-dimensional ordered mesoporous carbon (OMC) with tubular framework supported SnO2 nanoparticles entangled in MoS2 nanosheets is developed ingeniously by nanocasting and hydrothermal methods. The bimodal mesoporous interconnected architecture of CMK-9 and MoS2 nanosheets host SnO2 nanoparticles inside the mesopores and interlayer regions. Herein, for the first time, electrochemical performances of SnO2/MoS2 heterojunction are explored with an OMC. The present architecture improves the diffusion of ions and conduction of charges, which assist in achieving outstanding capacity, superior rate capability and stable cycle life when the nanocomposite is employed as the anode for lithium-ion batteries (LIBs). Among the nanocomposites, the SnO2/MoS2(1:3)@CMK-9 anode delivers a large initial discharge capacity of 2211 mA h g−1 and an outstanding discharge capacity of 1245 mA h g−1 after 300 cycles with a capacity retention of 96% as compared to the 3rd cycle (1291 mA h g−1) at a current density of 100 mA g−1. At a current density of 1000 mA g−1, the anode provides an exceptional discharge capacity of 823 mA h g−1 after 1000 cycles with capacity retention of 91% as compared to the 3rd cycle. The present architecture of SnO2/MoS2(1:3)@CMK-9 nanocomposite anode with excellent electrochemical performances signifies its potential use in next generation LIBs.

Closely packed Si@C and Sn@C nano-particles anchored by reduced graphene oxide sheet boosting anode performance of lithium ion batteries

Both silicon and tin are promising anodes for new generation lithium ion batteries due to high lithium storage capacities (theoretically 4200 mA h g−1 and 992 mA h g-1, respectively). However, their large volumetric expansions (both are above 300 %) usually lead to poor cycling stability. In this case, we synthesized closely packed Si@C and Sn@C nano-particles anchored by reduced graphene oxide (denoted as Si@C/Sn@C/rGO) by the way of solution impregnation and subsequent hydrogenation reduction. Sn particles with a diameter of 100 nm are coated by carbon and surrounded by Si@C particles around 40 nm in average diameter through the high-resolution transmission electron microscopy. Expansions of Si and Sn are alleviated by carbon shells, and reduced graphene oxide sheets accommodate their volume changes. The prepared Si@C/Sn@C/rGO electrode delivers an enhanced initial coulombic efficiency (78 %), rate capability and greatly improved cycle stability (a high reversible capacity of nearly 1000 mA h g−1 is achieved after 300 cycles at a current density of 1000 mA g−1). It can be believed that packing Sn@C nano-particles with Si@C relieves the volume expansion of both and releases the expansion stresses. Sn@C particles enhance anode process kinetics by reducing charge transfer resistance and increasing lithium ion diffusion coefficient. The present work provides a viable strategy for facilely synthesizing silicon-tin-carbon composite anode with long life.

Electrochemical Performance Enhancement of Micro-Sized Porous Si by Integrating with Nano-Sn and Carbonaceous Materials.

Silicon is investigated as one of the most prospective anode materials for next generation lithium ion batteries due to its superior theoretical capacity (3580 mAh g−1), but its commercial application is hindered by its inferior dynamic property and poor cyclic performance. Herein, we presented a facile method for preparing silicon/tin@graphite-amorphous carbon (Si/Sn@G–C) composite through hydrolyzing of SnCl2 on etched Fe–Si alloys, followed by ball milling mixture and carbon pyrolysis reduction processes. Structural characterization indicates that the nano-Sn decorated porous Si particles are coated by graphite and amorphous carbon. The addition of nano-Sn and carbonaceous materials can effectively improve the dynamic performance and the structure stability of the composite. As a result, it exhibits an initial columbic efficiency of 79% and a stable specific capacity of 825.5 mAh g−1 after 300 cycles at a current density of 1 A g−1. Besides, the Si/Sn@G–C composite exerts enhanced rate performance with 445 mAh g−1 retention at 5 A g−1. This work provides an approach to improve the electrochemical performance of Si anode materials through reasonable compositing with elements from the same family.

1- (P-toluenesulfonyl)imidazole (PTSI) as the novel bifunctional electrolyte for LiCoO2-based cells with improved performance at high voltage

Higher charging cutoff voltages of LiCoO2/graphite pouch-cells with high energy density can meet the advanced requirement of new generation lithium-ion batteries. However, the poor cycling performance derives from severe the electrolyte's decomposition on interface of the cathode/electrolyte at high charging cutoff voltage limits its wider commercial application. To resolve these detrimental effects of battery at high operating voltage, a novel bifunctional electrolyte additive (PTSI) is added into electrolyte for the LiCoO2/graphite pouch-cells. Upon operating at higher charging cut-off voltage (4.4 V) after 200 cycles, the LiCoO2/graphite pouch-cells with 1.0 wt.% PTSI in the electrolyte reveals preferable cycle performance over those in baseline electrolyte. The capacity retention of the pouch-cells with 1.0 wt. % PTSI in the electrolyte is 95.33% after 200 cycles, which is only 61.74% for those in baseline electrolyte. The results of electrochemical and spectroscopic techniques indicate that PTSI decomposes before the electrolyte solvents are consumed, and then took part in the interface layer formation on the interfaces of the electrodes, improving the cells performance. This work develops the novel bifunctional electrolyte additive that meets the requirement of a LiCoO2-based pouch-cells at high voltage.

Dual confinement of carbon/TiO2 hollow shells enables improved lithium storage of Si nanoparticles

Silicon is regarded as one of the most promising anode materials for next generation lithium-ion batteries (LIBs). However, the severe volume changes during lithiation/delithiation, leading to fast capacity decay and reduced cycling life, remains an obstacle to its practical application. In this work, we propose the design of a yolk-shell structure of carbon@TiO2@Si (CTS) by template process based on sol-gel chemistry. The Si nanoparticles are confined in the carbon/TiO2 double shells with abundant void space between the Si core and carbon/TiO2 shells. The yolk-shell architecture with concentric double shells substantially improves the structure stability of the electrodes. Consequently, the CTS delivers a high capacity of 747 mA h g−1 at a current density of 100 mA g−1, which is far superior to that (356 mA h g−1) of C@Si (CS) with only a single carbon shell. The double-shelled confinement strategy proposed in this work sheds some light on the development of improved Si-based anode for next-generation LIBs.

Effect of Size and Shape on Electrochemical Performance of Nano-Silicon-Based Lithium Battery.

Silicon is a promising material for high-energy anode materials for the next generation of lithium-ion batteries. The gain in specific capacity depends highly on the quality of the Si dispersion and on the size and shape of the nano-silicon. The aim of this study is to investigate the impact of the size/shape of Si on the electrochemical performance of conventional Li-ion batteries. The scalable synthesis processes of both nanoparticles and nanowires in the 10–100 nm size range are discussed. In cycling lithium batteries, the initial specific capacity is significantly higher for nanoparticles than for nanowires. We demonstrate a linear correlation of the first Coulombic efficiency with the specific area of the Si materials. In long-term cycling tests, the electrochemical performance of the nanoparticles fades faster due to an increased internal resistance, whereas the smallest nanowires show an impressive cycling stability. Finally, the reversibility of the electrochemical processes is found to be highly dependent on the size/shape of the Si particles and its impact on lithiation depth, formation of crystalline Li15Si4 in cycling, and Li transport pathways.