High-capacity Anode Materials Research Articles

Slow Voltage Relaxation of Silicon Nanoparticles with a Chemo-Mechanical Core-Shell Model.

Silicon presents itself as a high-capacity anode material for lithium-ion batteries with a promising future. The high ability for lithiation comes along with massive volume changes and a problematic voltage hysteresis, causing reduced efficiency, detrimental heat generation, and a complicated state-of-charge estimation. During slow cycling, amorphous silicon nanoparticles show a larger voltage hysteresis than after relaxation periods. Interestingly, the voltage relaxes for at least several days, which has not been physically explained so far. We apply a chemo-mechanical continuum model in a core-shell geometry interpreted as a silicon particle covered by the solid-electrolyte interphase to account for the hysteresis phenomena. The silicon core (de)lithiates during every cycle while the covering shell is chemically inactive. The visco-elastoplastic behavior of the shell explains the voltage hysteresis during cycling and after relaxation. We identify a logarithmic voltage relaxation, which fits with the established Garofalo law for viscosity. Our chemo-mechanical model describes the observed voltage hysteresis phenomena and outperforms the empirical Plett model. In addition to our full model, we present a reduced model to allow for easy voltage profile estimations. The presented results support the mechanical explanation of the silicon voltage hysteresis with a core-shell model and encourage further efforts into the investigation of the silicon anode mechanics.

Hierarchical porous silicon oxycarbide as a stable anode material for lithium-ion batteries

The porous and amorphous silicon oxycarbides (SiOC) derived from polymer precursors are regarded as promising anode materials for lithium-ion batteries due to their high theoretical capacity and minimal volume expansion. Modulations of carbon nanoclusters and reversible species in Si-O-C units have been performed to improve lithium storage properties of SiOC anodes. Herein, we report the effects of pore structure on cycling stability and rate performance of SiOC anode materials, which are prepared by a sol-gel approach using different additions of solvents and a subsequent calcination. The increase in the solvent addition promotes the formation of macropores in the hierarchical porous structure of the SiOC, thereby facilitating rapid Li ion migration and mitigating volume expansion during the lithiation of the SiOC. The as-prepared SiOC anode exhibits competitive reversible capacities of 750.4 mAh g−1 at 0.1 A g−1 after 150 cycles and 437.1 mAh g−1 at 1 A g−1 after 500 cycles, compared to those of previously reported SiOC anodes. This work provides a new strategy for designing of high-capacity and high-stability SiOC anode materials.

In-situ construction of heterogeneous structure by crystal phase evolution to improve the sodium storage performance of NiCo2O4

Transition metal oxides (TMCs) have great potential in sodium ion batteries (SIBs) due to their significantly higher capacity and lower cost. However, during the cycle, huge volume changes often lead to structural damage, which is a key factor in the rapid decay of capacity. In this paper, a heterogeneous structure was constructed in situ by introducing sulfur element to induce the decomposition of NiCo2O4 crystal phase. The rich heterogeneous interface has enhanced redox reaction kinetics and charge transport properties. For high-capacity conversion anode materials, cross-linked grain boundaries can effectively disperse the local stress caused by volume changes and alleviate the inevitable electrode crushing, thus ensuring the stability of the electrode during long-term cycling. The NiCo2O4/NiCo2S4/CoO/ NiO heterogeneous structure (NCOS-350) exhibits enhanced cycling and rate performance (350 mAh g−1 at 0.5 A g −1 after 100 cycles and 270 mAh g −1 at 5 A g −1) when used as the anode for sodium ion batteries. In addition, it is proved that NCOS-350 has smaller volume change and better structural stability than NiCo2O4 by scanning electron microscopy and other characterizations.

Hydrothermal Synthesis of Hierarchical Cage-like Co9S8 Microspheres Composed of Nanosheets as High-Capacity Anode Materials

Hydrothermal Synthesis of Hierarchical Cage-like Co9S8 Microspheres Composed of Nanosheets as High-Capacity Anode Materials

A Novel Gelatin Binder with Helical Crosslinked Network for High-Performance Si Anodes in Lithium-Ion Batteries.

Silicon(Si) is a promising anode material for lithium-ion batteries, but its large volume expansion during cycling poses a challenge for the binder design. In this study, a novel gelatin binder is designed and prepared with a helical crosslinked network structure. This gelatin binder is prepared by enzymatic crosslinking and immersion in Hofmeister salt solution, which induces the formation of network and helical secondary structures. The helical crosslinked network structure can be analogous to a spring group system to effectively dissipate the stress and strain caused by the Si expansion. The gelatin binder is further partially carbonized by low-temperature pyrolysis, which improves its conductivity and stability. The Sianode with the optimized gelatin binder exhibits high initial coulombic efficiency, excellent rate performance, and long-term cycling stability. This study provides an innovative approach for the preparation of high-performance Si anodes, namely by controlling the molecular configuration of the binder to significantly improve the cycle stability, which can also be applied to other high-capacity anode materials that suffer from large volume changes during cycling.

Fly-ash derived crystalline Si (cSi) Improves the capacity and energy density of LiNi0.8Co0.1Mn0.1O2 battery: Synthesis and performance

For decades, graphite has been the key ingredient in the anode of Li-ion batteries (LIBs). The search for high-capacity anode materials for Li-ion batteries (LIBs) has led to increasing interest in silicon (Si) as a potential replacement for graphite. This study presents an innovative approach to synthesizing crystalline Si (cSi) from type C fly ash, addressing both the need for improved LIB anodes and the challenge of industrial waste management. Our novel process involves a stepwise method of extraction, gelation using various mineral acids (HCl, H2SO4, and HNO3), magnesiothermic reduction, and purification. X-ray diffraction and energy-dispersive X-ray spectroscopy confirmed the production of high-purity SiO2 and cSi. Notably, a cSi-doped graphite anode (5 % Si) paired with LiNi0.8Mn0.1Co0.1O2 (NMC811) in a cylindrical cell achieved a minimum specific discharge capacity of 388 mAh/ganode after formation, surpassing the theoretical capacity of graphite (372 mAh/g). This demonstrates that even a small amount of cSi can significantly enhance anode performance. Our scalable, simple, and economical process offers a dual benefit: improving battery characteristics while providing an efficient method for fly ash waste utilization. This approach paves the way for sustainable production of high-performance LIB anodes while addressing critical waste management challenges.

Template-directed strategy synthesis of CoNi-layered double hydroxide nanosheet coated with polypyrrole for enhanced capacitive deionization

Recently, faradic material layered double hydroxide (LDH) has been widely used as an anode for capacitive desalination (CDI), due to its reversible ion insertion/deintercalation process and high anion storage capacity. Unfortunately, the issues of poor conductivity and self-stacking of LDH limit its application in the CDI. Herein, CoNi-LDH coated with polypyrrole (PPy@CoNi-LDH) was meticulously designed and synthesized using ZIF-67 as the precursor by template-directed strategy and in-situ polymerization. The CoNi-LDH has large interlayer distance of 0.91 nm, which is beneficial for ion insertion. Introduced PPy conductive layer improved the interface transfer rate of charges and increased the ion storage capacity of composite. The experimental test results indicate that PPy@CoNi-LDH1:1 electrode has a higher specific capacitance of 223.1 F g−1 and lower resistivity of 62.33 Ω·cm compared to CoNi-LDH electrode (35.2 F g−1 and 3.39 × 104 Ω·cm). Obtained PPy@CoNi-LDH1:1 also has abundant mesoporous and excellent hydrophilicity, which can promote ions transfer. Meanwhile, the specific surface area of PPy@CoNi-LDH1:1 with the coating structure is 1.78 times that of CoNi-LDH, effectively suppressing the self-stacking of CoNi-LDH and exposing more active sites. When employed PPy@CoNi-LDH1:1 as an anode and the activated carbon as a cathode, the PPy@CoNi-LDH1:1//AC cell exhibited a high Cl− removal capacity (60.20 mg g−1), a swift Cl− removal rate (11.45 mg g−1 min−1) and good cycling stability (the retention rate is 89.67 % after 50 cycles) in NaCl solution of 500 mg L−1 and 1.4 V applied voltage. Additionally, the adsorption mechanism indicated that surface charge attraction, ligand exchange, and ion insertion jointly promote the Cl− removal. This study provides a feasible solution about successful design of high adsorption capacity anode materials for CDI.

Metal-organic framework-derived in situ-grown Cu2Sb@NC octahedra for high-performance stable lithium/sodium storage

Intermetallic compounds are considered a special class of alloy-type anode materials that show great potential for use in lithium/sodium-ion batteries due to their inherent advantages, such as high specific capacity and enhanced safety features. However, their practical application is often impeded by the substantial volume changes that occur during the insertion and extraction of Li+/Na+ ions, leading to capacity decay and reduced service life. To address this challenge, we developed a novel composite material comprising Cu2Sb nanoparticles encapsulated within a N-doped octahedral carbon matrix (Cu2Sb@N-C). This composite structure features a heteroatom-doped conductive network, a three-dimensional carbon framework, and finely dispersed Cu2Sb nanoparticles. Benefiting from the heteroatom-doped conductive network, three-dimensional carbon framework and ultrafine Cu2Sb nanoparticles, they not only provide a penetrating network for the fast transfer of charge carriers and improve the accessibility of ions, but also alleviate the agglomeration and volume expansion of Cu2Sb during cycling. For LIBs, the material exhibited a reversible capacity of 1001.0 mAh/g after 330 cycles at 0.2 A/g, while maintaining a substantial capacity of 565.5 mAh/g after 1000 cycles at 1.0 A/g. In the case of SIBs, the material exhibited a capacity of 375.6 mAh/g after 100 cycles at 0.2 A/g. Post-cycling electrode analyses revealed that the Cu2Sb@N-C anode material retained its structural integrity, demonstrating its ability to withstand the continuous insertion and extraction of Li+/Na+ ions. This research contributes insights into the effective design of innovative high-capacity alloy-based anode materials for advanced secondary batteries.

Facile One-Pot Synthesis of Fe3O4 Nanoparticles Composited with Reduced Graphene Oxide as Fast-Chargeable Anode Material for Lithium-Ion Batteries.

To address the rapidly growing demand for high performance of lithium-ion batteries (LIBs), the development of high-capacity anode materials should focus on the practical perspective of a facile synthetic process. In this work, iron oxide nanoparticles (Fe3O4 NPs) in situ grown on the surface of reduced graphene oxide (rGO), denoted as Fe3O4 NPs@rGO, were prepared through a facile one-pot synthesis under the wet-colloidal conditions. The synthesized Fe3O4 NPs showed that uniform Fe3O4 NPs, with a size of around 9 nm, were distributed on the rGO surfaces. When applied as an anode material for LIBs, the Fe3O4 NPs@rGO anode revealed a high reversible capacity of 1191 mAh g-1 at 1.0 A g-1 after 200 cycles. It also exhibited excellent rate performance, achieving 608 mAh g-1 at a current density of 5.0 A g-1 over 500 cycles, with improved electronic and ionic conductivities due to the rGO template. This suggested that practically available anode materials can be developed through our one-pot synthesis by in situ growing the Fe3O4 NPs.

Synergy of Artificial SEI and Electrolyte Additive for Improved Performance of Silicon Electrodes in Li-Ion Batteries.

Maintaining the electrochemically and mechanically stable solid electrolyte interphase (SEI) is of highest importance for the performance of high-capacity anode materials such as silicon (Si). Applying flexible Li-ion permeable coatings to the electrode surface using molecular layer deposition (MLD) offers a strategy to improve the properties of the SEI and greatly contributes to an increase in the cycle life and capacity retention of Si electrodes. In this study, the long-term cycling of Si electrodes with an MLD alucone coating is investigated in the context of more stable SEI formation. When the joined strategy introducing both MLD coating and anFEC electrolyte additive was realized, high performance of Si anodes was achieved, capable of delivering more than 1500 mAh g-1 even after 400 cycles. The reason for the significantly improved longevity is the ability of the alucone layer to react with HF present in LiPF6-based electrolytes already under OCV-like conditions, fluorinating most of the available -OH groups in the alucone structure. This reaction not only partially scavenges hydrofluoric acid but also does not disturb the confining effect of alucone-like fluorinated artificial SEI. This study shows the significance of searching for synergetic solutions, such as a combination of electrode surface modification and electrolyte composition, for maximizing the capacity retention of Si as an active material or as a capacity-enhancing additive to graphite electrodes, and as well can be applied to other high-energy battery materials with large volume changes during cycling.

Exploring Mo2B MBene as a high-capacity anode material for multi-valent metal-ion batteries: Insights from first-principles calculations

A novel class of 2-dimensional (2D) materials, known as MBenes, has recently been proposed as a promising candidate for electrode applications in metal-ion batteries due to their high conductivity and rich chemistry. In this study, we present a computational investigation into the potential of Mo2B MBene as an anode material for Na-, Mg-, and Al-ion batteries. Using density functional theory (DFT) calculations, we examine the structural, electronic, and electrochemical properties of both H- and T-type configurations of Mo2B. Our findings reveal that Mo2B exhibits metallic behavior and excellent metal adsorption characteristics, with Al exhibiting the strongest binding affinity, followed by Mg and Na. This strong binding, especially with Al, although results in higher diffusion barriers, it enhances layer adsorption leading to increased theoretical capacity. The calculated maximum capacities are significant, with Al (1323 mAh g−1) showing the highest capacity, followed by Mg (923 mAh g−1) and Na (216 mAh g−1). Additionally, the open-circuit voltage (OCV) for all metals ranges between 0.1 and 1.0 V, suggesting the suitability of Mo2B MBene as an anode material that minimizes dendrite formation risks. These results indicate the potential of Mo2B for high-performance multi-valence ion batteries, with particular promise for Al-ion batteries due to their superior capacity. Furthermore, we propose that strain engineering could optimize Mo2B for enhanced performance in Na-ion batteries. Overall, this study suggests Mo2B MBene as a highly promising anode material for next-generation metal-ion batteries, offering significant advantages in terms of capacity, voltage, and safety. Our findings provide insights that could be used for further experimental design of Mo2B-based anodes for energy storage technologies.

Advancements in Lithium-Ion Battery Technology

Lithium-ion (Li-ion) batteries are at the forefront of modern energy storage technologies due to their high energy density, long cycle life, and relatively low self-discharge rate. Recent advancements in materials science, battery management systems, and fabrication techniques have significantly improved the performance, safety, and sustainability of Li-ion batteries. This paper explores the latest developments in lithium-ion technology, including high-capacity anode and cathode materials, solid-state electrolytes, and next-generation designs, while also addressing the challenges and future directions for research and application.

A cubic perovskite fluoride anode with the surface conversion reactions dominated mechanism for advanced lithium-ion batteries.

Perovskite fluorides are attractive anode materials for lithium-ion batteries (LIBs) because of their three-dimensional diffusion channels and robust structures, which is advantageous for the rapid transmission of lithium ions. Unfortunately, the wide band gap results in poor electronic conductivity, which limits their further development and application. Herein, the cubic perovskite iron fluoride (KFeF3, KFF) nanocrystals (~100 nm) are synthesized by a one-step solvothermal strategy. Thanks to the good electrical conductivity of carbon nanotubes (CNTs), the overall electrochemical performance of composite anode material (KFF-CNTs) has been significantly improved. In particular, the KFF-CNTs delives a high specific capacity (363.8 mAh g-1), good rate performance (131.6 mAh g-1 at 3.2 A g-1), and superior cycle stability (500 cycles). Noted that the surface conversion reactions play a dominant role in the electrochemical process of KFF-CNTs, together with the stable octahedral perovskite structure and nanoscale particle sizes achieving high ion diffusion coefficients. Furthermore, the specific lithium storage mechanism of KFF has explored by the distribution of relaxation times (DRT) technology. This work opens up a new way for developing cubic perovskite fluorides as high-capacity and robust anode materials for LIBs.

Enhancing Tin Dioxide Anode Performance by Narrowing the Potential Range and Optimizing Electrolytes

Tin dioxide (SnO2) is a low-cost and high-capacity anode material for lithium-ion batteries, but the fast capacity fading significantly limits its practical applications. Current research efforts have focused on preparing sophisticated composite structures or optimizing functional binders, both of which increase material manufacturing costs. Herein, we utilize pristine and commercially available SnO2 nanopowders and enhance their cycling performance by simply narrowing the potential range and optimizing electrolytes. Specifically, a narrower potential range (0–1 V) mitigates the capacity fading associated with the conversion reaction, whereas an ether-based electrolyte further suppresses the volume expansion related to the alloy reaction. Consequently, this SnO2 anode delivers a promising battery performance, with a high capacity of ~650 mAhg−1 and stable cycling for 100 cycles. Our work provides an alternative approach to developing high-capacity and long-cycling metal oxide anode materials.

Elucidation on Abnormal Capacity Increase in SiO2@C Core-Shell Nanospheres Anode for Lithium-Ion Battery.

An abnormal capacity increase stage has been observed in nanostructured SiO2 after the initial capacity drop stage. To investigate the Li+ storage kinetic mechanism for each stage, SiO2@C core-shell nanospheres with a total diameter of ∼108 to 170 nm but an adjustable C shell thickness of ∼4 to 31 nm have been fabricated. First, the existence form and specific content of SiO2 nanoparticles with a size of ∼6-10 nm, which are embedded in the outer C shell of SiO2@C core-shell nanospheres, were confirmed by SEM, TEM, BET, and TGA, respectively. It was found that the initial stage for capacity drop happens at 15-43 cycles and is followed by an enhancement stage, which presents an increase of ∼120 to 180% in capacity relative to the lowest capacity value during cycling. Among them, the sample of P-1 with a diameter of 109 nm for the SiO2 core and thickness of 31 nm for the C shell delivers the highest specific capacity of 1060 mAh/g at 100 mA/g and a capacity increase rate of ∼180% through 300 cycles. XPS analysis for the delithiation process indicates that the capacity drop and increase stage involves the partial oxidation of Li silicate, which is correlated to the formation of Li2Si2O5. Our study can be used to explain the mechanism of the abnormal capacity increase phenomenon for the SiO2 anode and provide a high-capacity anode material for LIB application.

Electrochemical sodium storage properties in monolayer VOPO4: A density functional theory prediction

The unique structural properties of two-dimensional materials make them promising for energy storage applications. This work theoretically predicts for the first time that Monolayer VOPO4 (MNL VOPO4), exfoliated from the delithiated phase of tetragonal LiVOPO4, is stable at room temperature, exhibiting excellent thermodynamic and kinetic stability, thus making it a promising high-capacity anode material for sodium-ion batteries (SIBs). Compared to bulk VOPO4, the monolayer structure significantly reduces the sodium ion migration energy barrier from 1.006 to 0.0795 eV, thereby markedly enhancing sodium ion migration kinetics. MNL VOPO4 can adsorb up to 32 sodium ions, corresponding to a theoretical capacity of 634.88 mA h g−1 and an energy density of 895.18 Wh kg−1. Furthermore, the excellent structural stability of MNL VOPO4 favors its cycling performance during charge and discharge processes. This work provides theoretical insights for better utilizing and developing multi-atomic phosphate compounds as electrode materials for secondary batteries.

Hard carbon/graphene microfibers as a superior anode material for sodium-ion batteries

Hard carbon is one of the most promising anode materials for sodium-ion batteries (SIBs). However, it still suffers from low specific capacity and poor rate capability, which impede its practical application. Herein, one-dimensional hard carbon/graphene microfibers are synthesized by encapsulating hard carbon particles in graphene nanosheet using a wet-spinning technique followed by pyrolysis treatment. Benefiting from the unique structure, when used as the anode material for SIBs, the as-obtained hard carbon/graphene microfibers not only exhibit a high reversible capacity of 321 mAh g−1 at 0.1 C but also deliver long cycling stability and excellent rate capability, maintaining its capacity as 203 mAh g−1 even after 350 cycles at 1 C. In addition, the sodium storage mechanism of the as-prepared hard carbon/graphene microfibers is investigated by in-situ Raman technique. Moreover, a full cell adopting the hybrid microfiber as the anode and Na3V2(PO4)3 as the cathode exhibits high specific capacities of 291 mAh g−1 and 204 mAh g−1 at 0.2 C and 4 C (vs. anode), respectively. This work provides a sustainable and cost-effective strategy for the synthesis of high-capacity and stable hard carbon anode materials.

Zinc Dicyanamide: A Potential High-Capacity Negative Electrode for Li-Ion Batteries.

We demonstrate that the β-polymorph of zinc dicyanamide, Zn[N(CN)2]2, can be efficiently used as a negative electrode material for lithium-ion batteries. Zn[N(CN)2]2 exhibits an unconventional increased capacity upon cycling with a maximum capacity of about 650 mAh·g-1 after 250 cycles at 0.5C, an increase of almost 250%, and then maintaining a large reversible capacity of more than 600 mAh·g-1 for 150 cycles. Such an increased capacity is primarily attributed to the increased level of activity in the conversion reaction. A combination of conversion-type and alloy-type mechanisms is revealed in this anode material via advanced characterization studies and theoretical calculations. This mechanism, observed here for the first time in transition-metal dicyanamides, is probably responsible for the outstanding electrochemical performance. We believe that this study guides the development of new high-capacity anode materials.

C60 Fullerene-Reinforced Silicon Oxycarbide Composite Fiber Mats: Performance as Li-Ion Battery Electrodes.

Precursor-derived silicon oxycarbide (SiOC) has emerged as a potential high-capacity anode material for rechargeable Li-ion batteries. The polymer processing and pyrolysis route, a hallmark of polymer-derived ceramics, allows chemical interfacing with a variety of nanoprecursors and nanofiller phases to produce composites with low-dimensional structures such as fibers and coatings not readily attained in traditional sintered ceramics. Here, buckminsterfullerene or C60 was introduced as a filler phase in a hybrid precursor of 1,3,5,7-tetramethyl-1,3,5,7-tetravinyl-cyclotetrasiloxane (TTCS) along with polyvinylpyrrolidone or PVP as a spinning agent to fabricate electrospun fiber mats, which upon a high-heat treatment transformed to a C60-reinforced SiOC ceramic composite. Tested as the self-supporting working electrode in a Li-ion half-cell, C60-reinforced fiber mats show a much-improved reversible capacity (825 mA h g-1), nearly 100% Coulombic efficiency, and superior rate capability with low-capacity decay at high currents (only 25.5% decay at 800 mA g-1) compared to neat C60 and neat carbonized fiber electrodes.

Mechanistic Insight into Ion Transport in Layered Materials for Sodium-Ion Rechargeable Batteries

As a feasible alternative to Li-ion batteries (LIBs), Na-ion batteries (SIBs) are an emerging energy storage solution for electric vehicles, electronic devices, and large grid level energy storage systems. The TMD (transition metal dichalcogenides) component MoS2 and the NASICON structured-type NaxTi2(PO4)3 are two materials of interest as next-generation SIB materials. MoS2 is a 2D layered material with a graphene-like structure that can be used as a high-capacity anode or Na-ion host material as well as an electrocatalyst. Our experiments on the Al-doped 1T phase of MoS2 on reduced graphene oxide (rGO) nanosheets support demonstrated good electrochemical performance, such as 450, 400, etc. mAh/g at current densities of 0.05, 0.1 A/g. Experiments further revealed that Na-ion intercalation supports increased interlayer distance in 1T Al-MoS2@rGO, resulting in a stable phase structure. Density functional theory (DFT)-based simulations are utilized to study the intercalation properties of Na+ ions, in addition to GITT, EIS, and CV analysis. In this study, the Na-ion diffusion mechanism for 1T Al-MoS2@rGO interface and Al-MoS2-MoS2 interlayer host structure is explored. According to the experiments, the host structure is doped with 5% Al at a specific stable site, and Na-ions are introduced to the interface and interlayer (an interlayer distance of 9.3 Å is chosen, as estimated by the experiments). The Na-ion is hopped in both structures, and activation energies (Eact) are calculated to be 57.9 kJ/mol and 40.3 kJ/mol in the 1T Al-MoS2@rGO interface at migration distances of 0-2 Å and 2-4 Å, respectively. The related Na-ion diffusion coefficients are computed using an Arrhenius type fit to be in the order of 10-13 cm2/s and 10-10 cm2/s. Similarly, the Na-ion activation energy barriers in the 1T Al-MoS2-MoS2 interlayer are estimated to be between 49.8 and 59.6 kJ/mol, with related diffusivity ranging between 10-11 and 10-13 cm2/s. The outcomes of the DFT simulations are consistent with those of our experiments. The Na-ion transport properties in the NaTi2(PO4)3 bulk structure via the Na-ion vacancy assisted mechanism are investigated using MD simulations and DFT. The self-diffusion coefficients (DNa+) of bulk are examined, and then the lattice strain effect is proposed to alter its transport properties by introducing the lattice strain in uniaxial (x, y, z) and biaxial (xy, xz, yz) directions, and the changes are compared for strained and unstrained structure. In comparison to the unstrained structure at 323K, a significant improvement by 1-2 order change in DNa+ values (10-8 cm2/s - 10-10 cm2/s) is measured. DFT is also used to investigate the diffusion mechanisms along the various planes (line [001], [100], and [010]) of the bulk NaTi2(PO4)3 structure and Eact is determined along those directions, respectively. The values obtained are consistent with the experimental value ranges obtained for similar materials. In addition, a mixed ion-system is represented by inserting Li-ions at the surface of a NaTi2(PO4)3 structure, yielding the formula LixNay-xTi2(PO4)3. The sluggish kinetics of Li-ion in the NaTi2(PO4)3 structure were proposed by MD analysis. This corresponds well with experimental data that the NaTi2(PO4)3 framework exhibits preferred Na-ion insertion when cycling in mixed-ion electrolytes of varied concentrations, implying slow diffusion of Li-ions in the bulk Li+/Na+ mixed-ion crystal.