Hongjiang Liu

Integrated Fast Assembly of Free-Standing Lithium Titanate/Carbon Nanotube/Cellulose Nanofiber Hybrid Network Film as Flexible Paper-Electrode for Lithium-Ion Batteries

A free-standing lithium titanate (Li4Ti5O12)/carbon nanotube/cellulose nanofiber hybrid network film is successfully assembled by using a pressure-controlled aqueous extrusion process, which is highly efficient and easily to scale up from the perspective of disposable and recyclable device production. This hybrid network film used as a lithium-ion battery (LIB) electrode has a dual-layer structure consisting of Li4Ti5O12/carbon nanotube/cellulose nanofiber composites (hereinafter referred to as LTO/CNT/CNF), and carbon nanotube/cellulose nanofiber composites (hereinafter referred to as CNT/CNF). In the heterogeneous fibrous network of the hybrid film, CNF serves simultaneously as building skeleton and a biosourced binder, which substitutes traditional toxic solvents and synthetic polymer binders. Of importance here is that the CNT/CNF layer is used as a lightweight current collector to replace traditional heavy metal foils, which therefore reduces the total mass of the electrode while keeping the same areal loading of active materials. The free-standing network film with high flexibility is easy to handle, and has extremely good conductivity, up to 15.0 S cm(-1). The flexible paper-electrode for LIBs shows very good high rate cycling performance, and the specific charge/discharge capacity values are up to 142 mAh g(-1) even at a current rate of 10 C. On the basis of the mild condition and fast assembly process, a CNF template fulfills multiple functions in the fabrication of paper-electrode for LIBs, which would offer an ever increasing potential for high energy density, low cost, and environmentally friendly flexible electronics.

In Situ Carbonized Cellulose-Based Hybrid Film as Flexible Paper Anode for Lithium-Ion Batteries

Flexible free-standing carbonized cellulose-based hybrid film is integrately designed and served both as paper anode and as lightweight current collector for lithium-ion batteries. The well-supported heterogeneous nanoarchitecture is constructed from Li4Ti5O12 (LTO), carbonized cellulose nanofiber (C-CNF) and carbon nanotubes (CNTs) using by a pressured extrusion papermaking method followed by in situ carbonization under argon atmospheres. The in situ carbonization of CNF/CNT hybrid film immobilized with uniform-dispersed LTO results in a dramatic improvement in the electrical conductivity and specific surface area, so that the carbonized paper anode exhibits extraordinary rate and cycling performance compared to the paper anode without carbonization. The flexible, lightweight, single-layer cellulose-based hybrid films after carbonization can be utilized as promising electrode materials for high-performance, low-cost, and environmentally friendly lithium-ion batteries.

Synthesis of cobalt-based layered coordination polymer nanosheets and their application in lithium-ion batteries as anode materials

Cobalt-based layered coordination polymer ([Co(tfbdc)(4,4′-bpy)(H2O)2] Co-LCP) nanosheets have been synthesized by a solvothermal method (H2tfbdc = tetrafluoroterephthalic acid, 4,4′-bpy = 4,4′-bipyridine). Powder X-ray diffraction, elemental analysis, IR spectra, thermogravimetric analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and the Brunauer–Emmett–Teller (BET) surface measurements were used to characterize the material. As an anode material for lithium-ion batteries, the Co-LCP nanosheets electrode exhibits higher reversible capacity and excellent cyclic stability, retaining 545 mA h g−1 after 50 cycles at a current density of 50 mA g−1.

Synthesizing nano-sized (∼20 nm) Li4Ti5O12 at low temperature for a high-rate performance lithium ion battery anode

In this paper, we developed a novel strategy to synthesize nano-sized Li4Ti5O12 (LTO) by hydrothermal method and calcination. X-ray diffraction and high resolution transmission electron microscopy were performed to characterize the structures and morphologies of these samples. Highly crystalline and pure-phase Li4Ti5O12 synthesized at low calcination temperature of 500 °C has been reported for the first time. This nanocrystalline LTO was tested as the anode material for lithium ion batteries, and exhibited excellent reversible capacities of 166, 162, 155, 142 and 123 mAh g−1 at current densities of 1 C, 2 C, 5 C, 10 C and 20 C, respectively. It also demonstrated good capacity retention and high coulombic efficiency values at all current rates. This excellent electrochemical performance makes our LTO a promising anode material for high energy/power density lithium ion batteries.

Coralloid-like Nanostructured c-nSi/SiOx@Cy Anodes for High Performance Lithium Ion Battery

Balancing the size of the primary Si unit and void space is considered to be an effective approach for developing high performance silicon-based anode materials and is vital to create a lithium ion battery with high energy density. We herein have demonstrated the facile fabrication of coralloid-like nanostructured silicon composites (c-nSi/SiOx@Cy) via sulfuric acid etching the Al60Si40 alloy, followed by a surface growth carbon layer approach. The HRTEM images of pristine and cycled c-nSi/SiOx@Cy show that abundant nanoscale internal pores and the continuous conductive carbon layer effectively avoid the pulverization and agglomeration of Si units during multiple cycles. It is interesting that the c-nSi/SiOx@C4.0 anode exhibits a high initial Coulombic efficiency of 85.53%, and typical specific capacity of over 850 mAh g-1 after deep 500 cycles at a current density of 1 A g-1. This work offers a facile strategy to create silicon-based anodes consisting of highly dispersed primary nano-Si units.

One-Dimensional Zinc-Based Coordination Polymer as a Higher Capacity Anode Material for Lithium Ion Batteries

A zinc-based one-dimensional (1D) coordination polymer ([Zn(H2mpca)2(tfbdc)(H2O)], Zn-ODCP) has been synthesized and characterized by spectroscopic and physicochemical methods, single-crystal X-ray diffraction, and thermogravimetric analysis (H2mpca = 3-methyl-1H-pyrazole-4-carboxylic acid; H2tfbdc = 2,3,5,6-tetrafluoroterephthalic acid). Zn-ODCP shows blue luminescence in the solid state. When Zn-ODCP acts as an anode material for lithium ion batteries, it exhibits a good cyclic stability and a higher reversible capacity of 300 mAh g-1 at 50 mA g-1 after 50 cycles. The higher capacity may be mainly ascribed to the metal ion and ligand all taking part in lithium storage. Searching for electrode materials of lithium ion batteries from 1D metal coordination polymers is a new route.

Functionalization of graphene oxide with naphthalenediimide diamine for high-performance cathode materials of lithium-ion batteries

Through the covalent bonding between naphthalenediimide diamine (NDIDA) and graphene oxide (GO), we synthesize NDIDA-functionalized graphene oxide (NDIDA-GO). The as-synthesized NDIDA-GO is characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and the Brunauer–Emmett–Teller surface area analysis. As a cathode material for lithium-ion batteries, within a voltage window of 4.5–1.5 V, NDIDA-GO exhibits a high specific capacity, good cyclic stability, and rate capability, keeping a specific capacity of 240 mA h g−1 after 50 cycles at 50 mA g−1. This work provides an effective route for the development of high-performance organic-based cathode materials for lithium-ion batteries.

Using Carboxylmethylated Cellulose as Water-Borne Binder to Enhance the Electrochemical Properties of Li 4 Ti 5 O 12 -Based Anodes

Abstract The present work reports a systematic study of using carboxymethylated cellulose (CMC) as water-bornebinder to produce Li 4 Ti 5 O 12 -based anodes for manufacture of high rate performance lithium ion batteries. When theLTO-to-CB-to-CMC mass ratio is carefully optimized to be 8:1:0.57, the special capacity of the resulting electrodes is144 mAh·g − 1 at 10 C and their capacity retention was 97.7% after 1000 cycles at 1 C and 98.5% after 500 cycles at5 C, respectively. This rate performance is comparable or even better than that of the electrolytes produced using con-ventional, organic, polyvinylidene fluoride binder. Keywords: Lithium titanate, CMC binder, Electrochemical properties, Long cycle life ······························································································································· ································································································· 1. Introduction Exhaust gas emitted from vehicles is one of the big-gest contributions to the increasingly serious environmen-tal pollution nowadays. Over the years, a considerablenumber of efforts have been put in development of envi-ronmental-friendly, green fuels for automobiles instead offossil fuels [1-3]. In this context, electric vehicles (EVs)and energy storage station (ESS) have been recentlydeveloped on the basis of use of high performance lith-ium ion batteries (LIBs) with long cycle life and highenergy density [4-9]. However, the stability and safety ofLIBs remain the big technical concerns, which limits thecommercialization of LIB [10,11]. To address these issues,novel electrode materials with larger lithium ion storageat high rate have been developed [12]. Among currently developed anode materials, spinelLi