Solid Li-ion Batteries Research Articles

Review on the recent progress in the nanocomposite polymer electrolytes on the performance of lithium‐ion batteries

In the recent decade, lithium-ion batteries have flourished in the mobile market to a greater extent. Despite its versatile commercial applications in various fields, it faces critical issues that restrict by safety concerns including leakage, combusting, or even explosions because of the low boiling point of liquid organic electrolytes. In order to mitigate these difficulties, solid electrolytes can be a potential choice. Polymer-based solid Li-ion batteries have been attracting researchers for accomplishing high performance. However, poor mechanical strength and low transport of Li+ ions inside the cell remain prominent challenges for its commercialization. To solve these issues and enhance the overall performance, polymer-based nanocomposite electrolytes developed by incorporating the nanofillers into the polymer matrix have been investigated to a greater extent. This review briefly elaborates on the recent progress of polymer nanocomposite electrolytes for lithium-ion batteries, factors affecting its performance, and various models used in the interpretation of its performance.

Recent Progress in Hybridized Nanogenerators for Energy Scavenging.

SummaryAs the world's demand for alternative energy increases, the development of green energy harvesters becomes ever more important. As a result, the creation of triboelectric (TENG), piezoelectric (PENG), and pyroelectric nanogenerators, electromagnetic generators (EMG), solar cells, and electrochemical cells is attracting interest in an effort to convert mechanical, thermal, magnetic, solar, and chemical energy into electricity. In order to take advantage of the ambient energies from our surrounding environment, the design of hybridized generator units that can simultaneously scavenge energy in a variety of forms continues to develop. These systems are being considered to satisfy the energy needs of a range of electronic devices and adapt to a variety of working environments. This review demonstrates the latest progress in hybridized nanogenerators in accordance with their structure, operating principle, and applications. These studies demonstrate new approaches to developing hybrid techniques and novel assemblies for efficiently harvesting environmental energy from a number of sources.

Theoretical formulation of Li3a+bNaXb (X = halogen) as a potential artificial solid electrolyte interphase (ASEI) to protect the Li anode

A major problem against the realization of high energy density and safe solid Li-ion batteries lies in detrimental reactions at the interface between the lithium anode and the solid electrolytes. This makes it necessary to develop an artificial solid electrolyte interphase (ASEI) as an effective protective coating to the lithium anode, which is the "Holy Grail" to enable high energy density batteries owing to its extremely high capacity. Here in this work, we carried out high-throughput first-principles modelling in the framework of materials genome engineering to identify potential ASEIs based on lithium nitric halides Li3a+bNaXb (X: halogen F, Cl, Br, I). On the basis of comprehensive assessments covering material stability, ionic conductivity, elastic modulus, and electrochemical compatibility with Li and potential SSEs, we have identified lithium nitric halides such as Li6NCl3 as superb ASEI candidates in line with their adequate ionic conductivity and fairly wide electrochemical window from 0 to 2 V (vs. Li/Li+). This makes them compatible with the lithium anode and various well-recognized thiophosphate SSEs such as LGPS, Li6PS5Cl, and Li3PS4, which have typical reduction potentials around 1.71 V. Besides, the large elastic modulus (e.g. 61.12 GPa for Li6NCl3) could be highly effective against the formation of lithium dendrites.

Lithium Ion Conductivity in Double Antiperovskite Li6.5OS1.5I1.5: Alloying and Boundary Effects

Solid electrolytes based on theoretically identified double antiperovskite phases Li6OSI2 were successfully synthesized. Experimental characterization supported the theoretical prediction that S substitution of O leads to stabilization of the double antiperovskite structure and lattice softening to significantly enhance ionic conductivity, so that the total Li+ conductivity in Li6.5OS1.5I1.5 was two to three orders better than that of the best stoichiometric antiperovskite phase Li3OCl. However, both antiperovskite and double antiperovskite materials are fundamentally susceptible to surface reconstruction, which is behind significant boundary resistances typically known for materials based on antiperovskite hali-chalcogenides. Such a surface related problem was then effectively reduced through amorphous phase formation, thus offering a feasible route to exploit the full potential of this class of new materials as competitive candidates for solid Li-ion batteries.

First-Principles Calculations of Ionic Conduction in Olivine-Type Li<i><sub>x</sub></i>FePO<sub>4</sub>

Super ionic conductors are required for all solid Li ion batteries. Conduction mechanism of LixFePO4 has been revealed by first-principles calculations using plane-wave basis. Crystal structures were constructed using a unit cell and a 1 × 2 × 1 super cell. Transition of Li site occupation with the smallest energy fluctuation was searched through graph theory. Trajectories of Li ions and migration energies were obtained by Nudged Elastic Band Method. Results show the migrating atoms pass through faces of O polyhedra. At dilute limit of Li, a single ion migrated and had very low migration energy of 0.14 eV. Increasing the carrier concentration resulted in pairing of Li atoms and raised the migration energy. At higher concentration region, cooperative ionic conduction mechanisms of two Li ions occurred. Low migration energies were obtained to be 0.20 and 0.22 eV for x = 0.25 and 0.5 of LixFePO4, respectively. Considering the migration energy and carrier concentration, LixFePO4 with the concentration region 0.25 ≤ x ≤ 0.5 should have high ionic conductivity. These mechanisms would be applied to develop new superionic conductors.

Fabrication of solid-state secondary battery using semiconductors and evaluation of its charge/discharge characteristics

Li-ion batteries have attracted interest for use as storage batteries. However, the risk of fire has not yet been resolved. Although solid Li-ion batteries are possible alternatives, their performance characteristics are unsatisfactory. Recently, research on utilizing the accumulation of carriers at the trap levels of semiconductors has been performed. However, the detailed charge/discharge characteristics and principles have not been reported. In this report, we attempted to form new n-type oxide semiconductor/insulator/p-type oxide semiconductor structures. The battery characteristics of these structures were evaluated by charge/discharge measurements. The obtained results clearly indicated the characteristics of rechargeable batteries. Furthermore, the fabricated structure accumulated an approximately 5000 times larger number of carriers than a parallel plate capacitor. Additionally, by constructing circuit models based on the experimental results, the charge/discharge mechanisms were considered. This is the first detailed experimental report on a rechargeable battery that operates without the double injection of ions and electrons.

First-principles insight into the structural fundamental of super ionic conducting in NASICON MTi2(PO4)3 (M = Li, Na) materials for rechargeable batteries

The electrochemical property of solid electrolyte plays a key role in stabilizing and enhancing the performance of all solid Li-ion battery, which means numerous effort is necessitated to explore and design better solid electrolytes. In this context, density functional theory calculations (DFT) were employed to investigate the electronic structures and ionic transport properties of NASICON MTi2(PO4)3 (M = Li, Na) materials aiming to elucidate the fast-ionic conductivity mechanism. The calculation results demonstrated that during the M ion migration, the Li/Na ions exhibit in both vacancy assisted and interstitial hopping, while the interstitial Li/Na diffusion with activation energies of 0.25eV for Li and 0.49eV for Na, is the kinetically favorable transport mechanism in their thermo-dynamically equilibrated configurations. However, the appearance of the interstitial M ion is strongly related to the ionic defect states and temperature, which indicates in real condition, two kinds of diffusion mechanism exhibit synergistic effect on the ion transport to realize the fast ion conducting in MTi2(PO4)3 (M = Li, Na) materials.

Implanting a solid Li-ion battery into a triboelectric nanogenerator for simultaneously scavenging and storing wind energy

Wind energy scavenging and storage usually can be achieved by utilizing two different separated units, such as a triboelectic nanogenerator and a Li-ion battery with need of being periodically charged. Here, we report a new strategy of implanting a flexible solid Li-ion battery (SLB) into a triboelectic nanogenerator (TENG) for simultaneously scavenging and storing wind energy into chemical energy to achieve a self-charging system. The fabricated TENG can deliver an output voltage of about 135V and an output current of about 12μA, which can be utilized to effectively charge the SLB in the triboelectric vibration film of TENG. The SLB can be easily charged from 1.5V to 3.5V in about 55s by using a transformer and a rectifier to connect the TENG. This research provides a new route of energy scavenging and storage devices for self-charging systems.

Unity Convoluted Design of Solid Li‐Ion Battery and Triboelectric Nanogenerator for Self‐Powered Wearable Electronics

AbstractWearable electronics suffer from severe power shortage due to limited working time of Li‐ion batteries, and there is a desperate need to build a hybrid device including energy scavenging and storing units. However, previous attempts to integrate the two units are mainly based on simple external connections and assembly, so that maintaining small volume and low manufacturing cost becomes increasingly challenging. Here a convoluted power device is presented by hybridizing internally a solid Li‐ion battery (SLB) and a triboelectric nanogenerator (TENG), so that the two units are one inseparable entity. The fabricated device acts as a TENG that can deliver a peak output power of 7.4 mW under a loading resistance of 7 MΩ, while the device also acts as an SLB to store the obtained electric energy. The device can be mounted on a human shoe to sustainably operate a green light‐emitting diode, thus demonstrating potential for self‐powered wearable electronics.

Field-assisted sintering of Li1.3Al0.3Ti1.7(PO4)3 solid-state electrolyte

All solid Li-ion batteries display high stability and longevity but are hampered by the poor conductivity of most solid electrolytes. The influence of applied electrical fields during sintering on microstructure and electronic properties of lithium aluminum titanium phosphate (Li1.3Al0.3Ti1.7(PO4)3, LATP) electrolyte material was investigated by sintering LATP pellets under DC voltages of 0V, 2V, 10V, and 20V, followed by characterization via scanning electron microscopy (SEM) and impedance spectroscopy. The application of a DC voltage increased the relative density to a maximum of 95.5%. However, unlike reports on other material systems such as zirconia, a high DC voltage induced rather than restrained abnormal grain growth. Resistivity increased with applied voltage from 2.1kΩ·cm at 0V to 7.8kΩ·cm at 20V, which was attributed to the high faceting and poor grain to grain contact of the grains sintered under 10V and 20V.

In situ TEM observation of the structural transformation of rutile TiO₂ nanowire during electrochemical lithiation.

We present the first direct experimental proof that phase changes occur during the real-time lithiation of rutile TiO2 nanostructures, functioning as the anode of a solid Li-ion battery inside a transmission electron microscope.