Cycling Stability Research Articles

In Situ Polymerized Zwitterionic Copolymer Ionic Gel Electrolytes with High Performance for Lithium-Ion Batteries.

Gel electrolytes are a promising research direction due to their high safety. However, its poor room temperature conductivity along with complex preparation process hinder its practical application. In this article, a type of zwitterionic gel electrolyte is prepared by in situ polymerization. The introduction of charged but nonmigrating zwitterionic copolymer in the polymer chain is beneficial to the dissociation of the lithium salt, improving the ion transport of the electrolyte on this account. At room temperature, the conductivity of lithium ion reaches 9.1 × 10-4 S cm-1, which contributes to achieve excellent electrochemical performance at high rates. The assembled Li|LiFePO4 cell also shows a capacity retention rate of 90.5% after 150 cycles at 0.5 C at room temperature as well as remarkable cycle stability at 1 C. These offer a novel tactic for the efficient and safe commercial application of lithium-ion batteries.

Highly Crystalline Multivariate Prussian Blue Analogs via Equilibrium Chelation Strategy for Stable and Fast Charging Sodium-Ion Batteries.

Prussian blue analogs (PBAs) have been widely recognized as superior cathode materials for sodium-ion batteries (SIBs) owing to numerous merits. However, originating from the rapid crystal growth, PBAs still suffer from considerable vacancy defects and interstitial water, making the preparation of long-cycle-life PBAs the greatest challenge for its practical application. Herein, a novel equilibrium chelation strategy is first proposed to synthesize a high crystallinity (94.7%) PBAs, which is realized by modulating the chelating potency of strong chelating agents via "acid effect" to achieve a moderate chelating effect, forcefully breaking through the bottleneck of poor cyclic stability for PBAs cathodes. Impressively, the as-prepared highly crystalline PBAs represent an unprecedented level of electrochemical performance including ultra-long lifespan (10000 cycles with 86.32% capacity maintenance at 6Ag-1), excellent rate capability (82.0mAhg-1 at 6Ag-1). Meanwhile, by pairing with commercial hard carbon, the as-prepared PBAs-based SIBs exhibit high energy density (350Whkg-1) and excellent capacity retention (82.4% after 1500 cycles), highlighting its promising potential for large-scale energy storage applications.

Effect of Temperature on CO2 Adsorption onto Amine-Functionalized KIT-6 Adsorbents.

The mesoporous silica KIT-6 was synthesized and functionalized with 3-aminopropyltriethoxysilane (APTES) by grafting at 110 °C. The composites were prepared with three different concentrations of APTES: 20, 30 and 40 wt.%. The as-prepared samples were characterized by thermal gravimetric analysis in air and nitrogen atmosphere (TG/DTA), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction and nitrogen adsorption-desorption. In this study, CO2 adsorption-desorption was investigated using temperature programmed desorption mass spectrometry (TPD-MS) at different temperatures. The adsorption capacity of the prepared composites is 2.23 mmol CO2/g at 40 °C and decreases to 0.95 mmol/g at 70 °C. Regarding the efficiency of the amino groups, the best result was obtained for APTES-grafted KIT-6 at 40 °C, with 0.512 mmol CO2/mmol NH2. The results showed good cyclical stability in adsorption capacities even after nine adsorption-desorption cycles.

Activation of MOF Catalysts with Low Steric Hindrance via Undercoordination Chemistry for Efficient Polysulfide Conversion in Lithium–Sulfur Battery

AbstractLithium–sulfur (Li–S) batteries promise high theoretical energy density and cost‐effectiveness but grapple with challenges like the polysulfide shuttle effect and sluggish kinetics. Metal–organic framework (MOF) catalysts emerge as a leading solution, despite limited conductivity and high steric hindrance. This study employs undercoordination chemistry to modify Zn–Co bimetallic MOFs (D‐ZIF L), removing organic ligands from active centers. This process mitigates spatial hindrance, thereby promoting comprehensive contact between sulfur species and metal active centers, consequently enhancing the catalytic efficiency of MOFs. Moreover, undercoordination treatment of the metal active centers induces electron redistribution, augmenting electron density at the Fermi level of the metal elements, thereby ameliorating the intrinsic conductivity. Leveraging these advantages, fabricated Li–S batteries employing D‐ZIF L catalysts exhibited markedly mitigated shuttling effects and accelerated sulfur species conversion kinetics. Notably, a substantial reverse areal capacity of 5.0 mAh cm⁻2 is achieved after 100 cycles with an evaluated sulfur loading of 5.5 mg cm⁻2. Furthermore, a practical pouch cell demonstrated an initial capacity of 1.8 Ah at 85.8 mA with stable cycling for 50 cycles. This study underscores the potential of undercoordination chemistry in the development of highly conductive MOF catalysts with minimized steric hindrance, thereby advancing the prospects of Li–S battery technology.

N/S‐Doped Hierarchical Porous Bamboo Carbon Fibers with Ultra‐Large Surface Area and Highly Exposed Active Sites for Flexible Zinc‐Air Battery†

Comprehensive SummaryFacile mass transport channel and accessible active sites are crucial for binder‐free air electrode catalysts in rechargeable flexible zinc‐air battery (ZAB). Herein, a ZnS/NH3 dual‐assisted pyrolysis strategy is proposed to prepare N/S‐doped hierarchical porous bamboo carbon cloth (HP‐NS‐BCC) as binder‐free air electrode catalyst for ZAB. BCC fabric with abundant micropores is firstly used as flexible carbon support to facilitate the heteroatom‐doping and construct the hierarchical porous structure. ZnS nanospheres and NH3 activization together facilitate the electronic modulation of carbon matrix by N/S‐doping and optimize the macro/meso/micropores structure of carbon fibers. Benefiting from the highly‐exposed N/S‐induced sites with enhanced intrinsic activity, the optimized mass transport of biocarbon fibers, as well as the ultra‐large specific surface area of 2436.1 m2·g–1, the resultant HP‐NS‐BCC catalyst exhibits improved kinetics for oxygen reduction/evolution reaction. When applied to rechargeable aqueous ZABs, it achieves a significant peak power density of 249.1 mW·cm−2. As binder‐free air electrode catalyst, the flexible ZAB also displays stable cycling over 500 cycles with a minimal voltage gap of 0.42 V, showcasing promising applications in flexible electronic devices.

Inducing and Understanding Pseudocapacitive Behavior in an Electrophoretically Deposited Lithium Iron Phosphate Li-Metal Battery as an Electrochemical Test Platform.

Our study has effectively employed electrophoretic deposition (EPD) using AC voltage to develop a lithium iron phosphate (LFP) Li-ion battery featuring pseudocapacitive properties and improved high C-rate performance. This method has significantly improved the battery's specific capacity, achieving an impressive 100 mAhg-1 at a 5 C discharge rate, which showcases its superior high-rate capability. Additionally, the battery displayed excellent reversibility during its performance cycles. These results confirm the EPD method's efficacy in improving LFP electrode performance, yielding notable improvements in cycling stability and high-rate capability. The enhanced capacity and high-rate performance of the electrophoretic-deposited LFP electrodes are largely due to the fast kinetics facilitated by pseudocapacitive behavior-induced charge storage and a high Li-ion diffusion constant measured in our EPD-deposited LFP electrodes. This underscores the practicality of our approach and the development of a fundamental test platform to investigate the pseudocapacitive charge storage mechanism in electrodes with typical battery-like behavior.

Electrochemical Investigation of ZnS/NiO Nanocomposite based Symmetric Supercapattery

AbstractSupercapattery is an ideal energy storage device combining the features of supercapacitors and batteries, offers a high‐energy density as well as high‐power density with extended operational lifespan. In this work, zinc sulfide (ZnS) and zinc sulfide/nickel oxide (ZnS/NiO) nanocomposite was synthesized via chemical coprecipitation method and characterized using state‐of‐the‐art analytical tools. The ZnS/NiO electrode exhibited remarkable electrochemical performance as an electrode material than pure ZnS. The ZnS/NiO nanocomposite exhibited high crystallinity, and spherical nanoparticles with an average grain size of 20–40 nm having a homogeneous dispersion. The ZnS/NiO electrode exhibited an ultrahigh specific capacity of 1803.87 Cg−1 at a relatively low scan rate of 10 mVs−1 in a 1 M KOH solution from cyclic voltammetry and 393 Cg−1 at 16 Ag−1 from charge discharge measurements, and it showed exceptional cycling stability (98 % capacity retention after 1000 cycles). Furthermore, the ZnS/NiO symmetric supercapattery device exhibited 44.43 Fg−1 specific capacitance, 5.52 Wh kg−1 energy density, and 1600 Wkg−1 power density at current density of 0.8 Ag−1 in 1 M KOH solution from galvanostatic charge discharge. After 3000 cycles, the ZnS/NiO nanomaterial demonstrated promising cyclic stability of 95 %. The ZnS/NiO supercapattery nanocomposite might be considered as a potential hybrid electrode material for the future development of electrochemical energy storage devices.

Realization of Long‐Life Proton Battery by Layer Intercalatable Electrolyte

Proton batteries have attracted increasing interests because of their potential for grid‐scale energy storage with high safety and great low‐temperature performances. However, their development is significantly retarded by electrolyte design due to free water corrosion. Herein, we report a layer intercalatable electrolyte (LIE) by introducing trimethyl phosphate (TMP) into traditional acidic electrolyte. Different from conventional role in batteries, the presence of TMP intriguingly achieves co‐intercalation of solvent molecules into the interlayer of anode materials, enabling a new working mechanism for proton reactions. The electrode corrosion was also strongly retarded with expanded electrochemical stability window. The half‐cell therefore showed an outstanding long‐term cycling stability with 91.0% capacity retention at 5 A g−1 after 5000 cycles. Furthermore, the assembled full batteries can even deliver an ultra‐long lifetime with a capacity retention of 74.9% for 2 months running at ‐20 °C. This work provides new opportunities for electrolyte design of aqueous batteries.

Cu-Doped Spherical P2-Type Na0.7Fe0.23-xCuxMn0.77O2 Cathode for High-Performance Sodium-Ion Batteries.

Sodium-ion batteries (SIBs), owing to their abundant resources and cost-effectiveness, have garnered considerable interest in the realm of large-scale energy storage. The properties of cathode materials profoundly affect the cycle stability and specific capacity of batteries. Herein, a series of Cu-doped spherical P2-type Na0.7Fe0.23-xCuxMn0.77O2 (x = 0, 0.05, 0.09, and 0.14, x-NFCMO) was fabricated using a convenient hydrothermal method. The successful doping of Cu efficaciously mitigated the Jahn-Teller effect, augmented the electrical conductivity of the material, and diminished the resistance to charge transfer. The distinctive spherical structure remained stable and withstood considerable volumetric strain, thereby improving the cyclic stability of the material. The optimized 0.09-NFCMO cathode exhibited a high specific capacity of 168.6 mAh g-1 at 100 mA g-1, a superior rate capability (90.9 mAh g-1 at 2000 mA g-1), and a good cycling stability. This unique structure design and doping approach provides new insights into the design of advanced electrode materials for sodium-ion batteries.

Ultralong Lifespan Zero‐Cobalt/Nickel Prussian Blue Analogs Cathode Realized by Solid Solution Reaction Sodium Storage Mechanism

AbstractDespite their low cost and high specific capacity, the practical use of monoclinic Mn‐based Prussian blue analogs (Mn‐PBAs) is limited by poor cycling stability, primarily due to the structural degradation caused by the multiple phase transitions and Jahn–Teller effect associated with Mn3+ ions throughout the entire cycle. Herein, by synergistic incorporation of low‐cost Cu and Fe into the manganese sites of Mn‐PBAs, the ternary PBAs (T‐PBAs) achieve solid solution reaction of Na+ extraction and insertion, successfully eliminating the inherent multi‐phase transition from the sodium storage mechanism of T‐PBAs. Ex situ analysis and density functional theory calculations are employed to confirm that T‐PBAs consistently maintain a cubic phase with smaller lattice distortion rather than occur in conventional three‐phase transition during the charging and discharging processes, forcefully inhibiting the structural degradation of T‐PBAs. Therefore, the T‐PBAs showcase unprecedented cycling stability at both room temperature (10 000 cycles at 1 A g−1) and −20 °C (over 3000 h, 4200 cycles at 0.2 A g−1 without distinct capacity degradation), More importantly, when paired with commercial hard carbon, the T‐PBAs based sodium‐ion batteries exhibit excellent capacity retention (2000 cycles 76.8%), showcasing their immense potential in practical applications.

Vacancy‐Rich Ternary Iron Phosphoselenide Multicavity Nanorods: A Highly Reversible and Fast Anode for Sodium‐Ion Batteries

AbstractThe significance of exploring optimal electrode materials cannot be overstated, particularly in mitigating the critical issues posed by sluggish redox kinetics, significant volume variations, and severe structural collapse resulting from the insertion and extraction of sodium ions. These efforts are crucial for enhancing the longevity and rapid charging capabilities of sodium‐ion batteries (SIBs). Herein, a defect engineering strategy for the in situ encapsulation of single‐phase ternary iron phosphoselenide into porous carbon by robust chemical bonds with the formation of rod‐like multicavity nanohybrids (FePSe3@C) is presented. The incorporation of Se atom not only modulates the electronic structure of the central metal Fe atom and enhances the intrinsic electrical conductivity, but also generates numerous additional reaction sites and accelerates the reaction kinetics of FePSe3@C, as corroborated by theoretical calculations and kinetic analysis. Notably, the FePSe3@C demonstrates an outstanding rate capability of 321.7 mAh g−1 even at 20 A g−1 and long cycling stability over 1000 cycles. The sodium‐ion full cell, pairing the FePSe3@C anode with the Na3V2(PO4)3@C cathode, exhibits a remarkable energy density of 202 Wh kg−1, demonstrating its practical applicability. This work provides a controllable defect and morphology engineering strategy to construct advanced materials with fast charge transfer for high‐power/energy SIBs.

High Performance Aqueous Zinc-Ion Batteries Developed by PANI Intercalation Strategy and Separator Engineering.

Aqueous zinc-ion batteries (ZIBs) have attracted burgeoning attention and emerged as prospective alternatives for scalable energy storage applications due to their unique merits such as high volumetric capacity, low cost, environmentally friendly, and reliable safety. Nevertheless, current ZIBs still suffer from some thorny issues, including low intrinsic electron conductivity, poor reversibility, zinc anode dendrites, and side reactions. Herein, conductive polyaniline (PANI) is intercalated as a pillar into the hydrated V2O5 (PAVO) to stabilize the structure of the cathode material. Meanwhile, graphene oxide (GO) was modified onto the glass fiber (GF) membrane through simple electrospinning and laser reduction methods to inhibit dendrite growth. As a result, the prepared cells present excellent electrochemical performance with enhanced specific capacity (362 mAh g-1 at 0.1 A g-1), significant rate capability (280 mAh g-1 at 10 A g-1), and admirable cycling stability (74% capacity retention after 4800 cycles at 5 A g-1). These findings provide key insights into the development of high-performance zinc-ion batteries.

Influence of Polypyrrole on Phosphorus- and TiO2-Based Anode Nanomaterials for Li-Ion Batteries.

Phosphorus (P) and TiO2 have been extensively studied as anode materials for lithium-ion batteries (LIBs) due to their high specific capacities. However, P is limited by low electrical conductivity and significant volume changes during charge and discharge cycles, while TiO2 is hindered by low electrical conductivity and slow Li-ion diffusion. To address these issues, we synthesized organic-inorganic hybrid anode materials of P-polypyrrole (PPy) and TiO2-PPy, through in situ polymerization of pyrrole monomer in the presence of the nanoscale inorganic materials. These hybrid anode materials showed higher cycling stability and capacity compared to pure P and TiO2. The enhancements are attributed to the electrical conductivity and flexibility of PPy polymers, which improve the conductivity of the anode materials and effectively buffer volume changes to sustain structural integrity during the charge and discharge processes. Additionally, PPy can undergo polymerization to form multi-component composites for anode materials. In this study, we successfully synthesized a ternary composite anode material, P-TiO2-PPy, achieving a capacity of up to 1763 mAh/g over 1000 cycles.

Realization of Long-Life Proton Battery by Layer Intercalatable Electrolyte.

Proton batteries have attracted increasing interests because of their potential for grid-scale energy storage with high safety and great low-temperature performances. However, their development is significantly retarded by electrolyte design due to free water corrosion. Herein, we report a layer intercalatable electrolyte (LIE) by introducing trimethyl phosphate (TMP) into traditional acidic electrolyte. Different from conventional role in batteries, the presence of TMP intriguingly achieves co-intercalation of solvent molecules into the interlayer of anode materials, enabling a new working mechanism for proton reactions. The electrode corrosion was also strongly retarded with expanded electrochemical stability window. The half-cell therefore showed an outstanding long-term cycling stability with 91.0% capacity retention at 5 A g-1 after 5000 cycles. Furthermore, the assembled full batteries can even deliver an ultra-long lifetime with a capacity retention of 74.9% for 2 months running at -20 °C. This work provides new opportunities for electrolyte design of aqueous batteries.

Flexible self‐supporting organic cathode with interface engineering for high‐performance and wide‐temperature sodium‐ion batteries

AbstractFlexible electrode design with robust structure and good performance is one of the priorities for flexible batteries to power emerging wearable electronics, and organic cathode materials have become contenders for flexible self‐supporting electrodes. However, issues such as easy electrolyte solubility and low intrinsic conductivity contribute to high polarization and rapid capacity decay. Herein, we have designed a flexible self‐supporting cathode based on perylene‐3,4,9,10‐tetracarboxylic dianhydride (PTCDA), interfacial engineering enhanced by polypyrrole (PPy), and carbon nanotubes (CNTs), forming the interconnected and flexible PTCDA/PPy/CNTs using polymerization reaction and vacuum filtration methods, effectively curbing those challenges. When used as the cathode of sodium‐ion batteries, PTCDA/PPy/CNTs exhibit excellent rate capability (105.7 mAh g−1 at 20 C), outstanding cycling stability (79.4% capacity retention at 5 C after 500 cycles), and remarkable wide temperature application capability (86.5 mAh g−1 at −30°C and 115.4 mAh g−1 at 60°C). The sodium storage mechanism was verified to be a reversible oxidation reaction between two Na+ ions and carbonyl groups by density functional theory calculations, in situ infrared Fourier transform infrared spectroscopy, and in situ Raman spectroscopy. Surprisingly, the pouch cells based on PTCDA/PPy/CNTs exhibit good mechanical flexibility in various mechanical states. This work inspires more rational designs of flexible and self‐supporting organic cathodes, promoting the development of high‐performance and wide‐temperature adaptable wearable electronic devices.

CNT Composite β-MnO2 with Fiber Cable Shape as Cathode Materials for Aqueous Zinc-Ion Batteries.

Rechargeable aqueous zinc-ion batteries (AZIBs) have developed into one of the most attractive materials for large-scale energy storage owing to their advantages such as high energy density, low cost, and environmental friendliness. Nevertheless, the sluggish diffusion kinetics and inherent impoverished conductivity affect their practical application. Herein, the β-MnO2 composited with carbon nanotubes (CNT@M) is prepared through a simple hydrothermal approach as a high-performance cathode for AZIBs. The CNT@M electrode exhibits excellent cycling stability, in which the maximum specific discharge capacity is 259 mA h g-1 at 3 A g-1, and there is still 220 mA h g-1 after 2000 cycles. The specific capacity is obviously better than that of β-MnO2 (32 mA h g-1 after 2000 cycles). The outstanding electrochemical performance of the battery is inseparable from the structural framework of CNT and inherent high conductivity. Furthermore, CNT@M can form a complex conductive network based on CNTs to provide excellent ion diffusion and charge transfer. Therefore, the active material can maintain a long-term cycle and achieve stable capacity retention. This research provides a reasonable solution for the reliable conception of Mn-based electrodes and indicates its potential application in high-performance AZIB cathode materials.

In Situ Induced Interface Engineering in Hierarchical Fe3O4 Enhances Performance for Alkaline Solid-State Energy Storage.

Rechargeable aqueous batteries adopting Fe-based materials are attracting widespread attention by virtue of high-safety and low-cost. However, the present Fe-based anodes suffer from low electronic/ionic conductivity and unsatisfactory comprehensive performance, which greatly restrict their practicability. Concerning the principle of physical chemistry, fabricating electrodes that could simultaneously achieve ideal thermodynamics and fast kinetics is a promising issue. Herein, hierarchical Fe3O4@Fe foam electrode with enhanced interface/grain boundary engineering is fabricated through an in situ self-regulated strategy. The electrode achieves ultrahigh areal capacity of 31.45 mA h cm-2 (50 mA cm-2), good scale application potential (742.54 mA h for 25 cm2 electrode), satisfied antifluctuation capability, and excellent cycling stability. In/ex situ characterizations further validate the desired thermodynamic and kinetic properties of the electrode endowed with accurate interface regulation, which accounts for salient electrochemical reversibility in a two-stage phase transition and slight energy loss. This work offers a suitable strategy in designing high-performance Fe-based electrodes with comprehensive inherent characteristics for high-safety large-scale energy storage.

Mitigating Dissolution to Enhance the Performance of Pillar[5]quinone in Sodium Batteries

Sodium‐ion batteries using organic electrode materials are a promising alternative to state‐of‐the‐art lithium‐ion batteries. However, their practical viability is hindered by challenges such as a low specific capacity of the organic electrode materials, or their dissolution in the electrolyte. We herein present a double mitigation strategy to enhance the performance of pillar[5]quinone (P5Q) as positive electrode in sodium batteries. Using 5 M sodium bis(fluorosulfonyl)imide in succinonitrile as highly concentrated electrolyte, and encapsulating P5Q in CMK‐3 (Carbon Mesostructured by KAIST with hexagonally ordered rod‐like carbon domains) as templated ordered mesoporous carbon, we achieve a record cycling performance with improved cycling stability even at elevated temperature (40 °C). The P5Q@CMK‐3 composite electrode delivers 430 mAh g−1 specific discharge capacity at 0.2C rate with 90% retention over 200 cycles. This corresponds to an energy density of 831 Wh kg−1 (based on P5Q mass) and surpasses previous reports on pillarquinones. When operated at 40 °C, the P5Q@CMK‐3 composite electrodes deliver a specific discharge capacity of 438 mAh g−1 with 88% capacity retention over 500 cycles (0.02% per cycle). This study underscores the crucial role the electrolyte plays in advancing organic sodium batteries, offering a promising avenue for the future of sustainable energy technologies.

High-Performance Aqueous Zinc-Organic Battery with a Photo-Responsive Covalent Organic Framework Cathode.

Covalent organic framework (COF) materials, known for their robust porous character, sustainability, and abundance, have great potential as cathodes for aqueous Zn-ion batteries (ZIBs). However, their application is hindered by low reversible capacity and discharge voltage. Herein, a donor-acceptor configuration COF (NT-COF) is utilized as the cathode for ZIBs. The cell exhibits a high discharge voltage plateau of ≈1.4V and a discharge capacity of 214 mAh g-1 at 0.2 A g-1 when utilizing the Mn2+ electrolyte additive in the ZnSO4 electrolyte. A synergistic combination mechanism is proposed, involving the deposition/dissolution reactions of Zn4SO4(OH)6·4H2O and the co-(de)insertion reactions of H+ and SO4 2- in NT-COF. Meanwhile, the NT-COF with a donor-acceptor configuration facilitates efficient generation and separation of electron-hole pairs upon light exposure, thereby enhancing electrochemical reactions within the battery. This leads to a reduction in charging voltage and internal overvoltage, ultimately minimizing electricity consumption. Under ambient weather conditions, the cell exhibits an average discharge capacity of 430 mAh g-1 on sunny days and maintains consistent cycling stability for a duration of 200 cycles (≈19 days) at 0.2 A g-1. This research inspires the advancement of Zn-organic batteries for high-energy-density aqueous electrochemical energy storage systems or photo-electrochemical batteries.

Lithium titanate synaptic device imitating lithium-ion battery structure

With the growing prevalence of neuromorphic computing algorithms, there is a growing need for electronic synaptic devices. In this study, using Li4+x Ti5O12 (LTO) as the resistive switching layer, C as the lithium ions storage layer, and Li1+x Al x Ti2−x (PO4)3 (LATP) as ions transmission layer, a synaptic device is designed with the structure of Pt/C/LATP/LTO/PtSi to imitate the lithium-ion battery. Variation of the thickness of the LATP layer in the LTO device is explored to show the impact on the device’s synaptic performance. With a LATP thickness of 100 nm, the LTO synaptic device exhibits a high potentiation/depression cyclic stability of over 50 cycles, improved potentiation/depression linearity and smoothness. The synaptic potentiation/depression is ascribed to migration of lithium ions from the LTO layer. A conductance relaxation characteristic of the device is explained by battery self-discharge phenomenon. The battery effect in the LTO device also led to generation of electromotive force. The study of battery-imitating LTO synaptic device offers new perspectives on the connection between battery and analog synaptic device.