ABSTRACT
Titanium dioxide nanoparticles (TiO2-NPs) are a promising anode material for Lithium-ion batteries (LIBs) due to their good rate capability, low cost, non-toxicity, excellent structural stability, extended cycle life, and low volumetric change (â¼4%) during the Li+ insertion/de-insertion process. In the present paper, anatase TiO2-NPs with an average particle size of ~ 12 nm were synthesized via a green synthesis route using Beta vulgaris (Beetroot) extract, and the synthesized TiO2-NPs were evaluated as anode material in LIBs. Furthermore, we employed an aqueous binder (1:1 mixture of carboxy methyl cellulose and styrene butadiene) for electrode processing, making the process cost-effective and environmentally friendly. The results revealed that the Li/TiO2 half-cells delivered an initial discharge capacity of 209.7 mAh g-1 and exhibited superior rate capability (149 mAh g-1 at 20 C) and cycling performances. Even at the 5C rate, the material retained a capacity of 82.2% at the end of 100 cycles. The synthesis route of TiO2-NPs and the aqueous binder-based electrode processing described in the present work are facile, green, and low-cost and are thus practically beneficial for producing low-cost and high-performance anodes for advanced LIBs.
ABSTRACT
Lithium carboxymethyl cellulose (CMC-Li) is a promising novel water-based binder for lithium-ion batteries. The direct synthesis of CMC-Li was innovatively developed using abundant wood dissolving pulp materials from hardwood (HW) and softwood (SW). The resulting CMC-Li-HW and CMC-Li-SW binders possessed a suitable degree of substitutions and excellent molecular weight distributions with an appropriate quantity of long- and short-chain celluloses, which facilitated the construction of a reinforced concrete-like bonding system. When used as cathode binders in LiFePO4 batteries, they uniformly coated and dispersed the electrode materials, formed a compact and stable conductive network with high mechanical strength and showed sufficient lithium replenishment. The prepared LiFePO4 batteries exhibited good mechanical stability, low charge transfer impedance, high initial discharge capacity (â¼180 mAh/g), high initial Coulombic efficiency (99 %), excellent cycling performance (<3% loss over 200 cycles) and good rate capability, thereby outperforming CMC-Na and the widely used cathode binder polyvinylidene fluoride.
Subject(s)
Carboxymethylcellulose Sodium , Electric Power Supplies , Electrodes , Lithium , Wood , Lithium/chemistry , Wood/chemistry , Carboxymethylcellulose Sodium/chemistry , Phosphates/chemistry , Ions , IronABSTRACT
Novel water-based binder lithium carboxymethyl cellulose (CMC-Li) is synthesized by cotton as raw material. The mechanism of the CMC-Li as a binder is reported. Electrochemical properties of batteries' cathodes based on commercially available lithium iron phosphate (LiFePO4, LFP) and water-soluble binder are investigated. Sodium carboxymethyl cellulose (CMC-Na, CMC) and CMC-Li are used as the binder. After 200 cycles, compared with conventional poly(vinylidene fluoride) (PVDF) binder, the CMC-Li binder significantly improves cycling performance of the LFP cathode 96.7% of initial reversible capacity achieved at 175 mA h g(-1). Constant current charge-discharge test results demonstrate that the LFP electrode using CMC-Li as the binder has the highest rate capability, followed closely by those using CMC and PVDF binders, respectively. Electrochemical impedance spectroscopy test results show that the electrode using CMC-Li as the binder has lower charge transfer resistance than the electrodes using CMC and PVDF as the binders.