Search Results (3)

Anode-free lithium-ion batteries offer a volumetric energy density approximately 60% higher than that of conventional lithium-ion cells. Despite this advantage, they often experience rapid capacity degradation and a limited cycle life. Optimizing electrolyte formulations—particularly through the use of specific additives, solvents, and lithium salts—is essential to improving these systems. This study explores electrolytes composed of fluorinated and carbonate-based solvents applied in anode-free lithium-ion cells featuring copper as the anode substrate and Li_1.05Ni_0.33Mn_0.33Co_0.33O₂ as the cathode. In the present work, the ionic conductivity of electrolytes was studied by impedance spectroscopy, and the electrochemical parameters of anode-free lithium-ion cells were compared using these electrolyte solutions: lithium difluoro(oxalato)borat (LIDFOB) salts were used in a mixture of solvents such as fluoroethylene carbonate (FEC) and dimethoxyethane (DME) in a ratio of 3:7 and in a mixture of propylene carbonate (PC) and dimethoxyethane in a ratio of 3:7. Enhanced performance was observed upon the substitution of conventional carbonates with fluorinated co-solvents. The findings suggest that LiDFOB is a thermostable salt, and its high conductivity contributes to the formation and stabilization of the interface of solid electrolytes. The results indicate that at low temperature conditions, a double salt should be used for lithium current sources, for example, 0.4 M LiDFOB and 0.6 M LiBF₄, as well as electrolyte additives such as fluoroethylene carbonate and lithium nitrate. Full article

In this work, we designed a novel polyvinylidene fluoride (PVDF)@DNA solid polymer electrolyte, wherein DNA, as a plasticizer-like additive, reduced the crystallinity of the solid polymer electrolyte and improved its ionic conductivity. At the same time, due to its Lewis acid effect, DNA promotes the dissociation of lithium salts when interacting with lithium salt anions and can also fix the anions, creating more free lithium ions in the electrolyte and thus improving its ionic conductivity. However, owing to hydrogen bonding between DNA and PVDF, excess DNA occupies the lone pairs of electrons of the fluorine atoms on the PVDF molecular chains, affecting the conduction of lithium ions and the conductivity of the solid electrolyte. Hence, in this study, we investigated the effects of adding different DNA amounts to solid polymer electrolytes. The results show that 1% DNA addition resulted in the best improvement in the electrochemical performance of the electrolyte, demonstrating a high ionic conductivity of 3.74 × 10⁻⁵ S/cm (25 °C). The initial capacity reached 120 mAh/g; moreover, after 500 cycles, the all-solid-state batteries exhibited a capacity retention of approximately 71%, showing an outstanding cycling performance. Full article

Environmental impacts and resource availability are significant concerns for the future of lithium-ion batteries. This study focuses on developing novel fluorine-free electrolytes compatible with aqueous-processed cobalt-free cathode materials. The new electrolyte contains lithium 1,1,2,3,3-pentacyanopropenide (LiPCP) salt. After screening various organic carbonates, a mixture of 30:70 wt.% ethylene carbonate and dimethyl carbonate was chosen as the solvent. The optimal salt concentration, yielding the highest conductivity of 9.6 mS·cm⁻¹ at 20 °C, was 0.8 mol·kg⁻¹. Vinylene carbonate was selected as a SEI-stabilizing additive, and the electrolyte demonstrated stability up to 4.4 V vs. Li+/Li. LiFePO₄ and LiMn_0.6Fe_0.4PO₄ were identified as suitable cobalt-free cathode materials. They were processed using sodium carboxymethyl cellulose as a binder and water as the solvent. Performance testing of various cathode compositions was conducted using cyclic voltammetry and galvanostatic cycling with the LiPCP-based electrolyte and a standard LiPF6-based one. The optimized cathode compositions, with an 87:10:3 ratio of active material to conductive additive to binder, showed good compatibility and performance with the new electrolyte. Aqueous-processed LiFePO₄ and LiMn_0.6Fe_0.4PO₄ achieved capacities of 160 mAh·g⁻¹ and 70 mAh·g⁻¹ at C/10 after 40 cycles, respectively. These findings represent the first stage of investigating LiPCP for the development of greener and more sustainable lithium-ion batteries. Full article