Severe thermodynamic lattice oxygen evolution and accelerated interfacial parasitic reactions significantly deteriorate the electrochemical reversibility of ultrahigh-Ni cathodes (LiNi0.9Co0.05Mn0.05O2, NCM90), particularly under harsh operational conditions (4.5 V, 55 degrees C, and 5 C). Herein, a combined dual-modification strategy integrating Mg2+/Al3+ bulk gradient doping and spinel MgAl2O4 (MA) interfacial coating is proposed to concurrently modulate the structural thermodynamics and interfacial kinetics of NCM90. Electrochemical phase transition tracking (dQ/dV) and kinetic analyses (galvanostatic intermittent titration technique and electrochemical impedance spectroscopy) reveal that the robust Al-O bonds and Mg2+ "pillaring" effect thermodynamically mitigate lattice oxygen loss and alleviate the irreversible H2-H3 phase transition. Simultaneously, the MA coating acts as a robust physical barrier, suppressing the aggressive oxidative decomposition of the electrolyte and minimizing the accumulation of the charge-transfer resistance (R ct). Benefiting from this integrated electrochemical tuning, the dual-modified MA-NCM90 exhibits robust kinetics, retaining 46.8% of its capacity after 300 cycles at 4.5 V and 55 degrees C (a 17.7% improvement over pristine NCM90, delivering an extra 35.2 mAh g-1), alongside a good fast-charging capability at 5 C. This study elucidates the fundamental mechanism of bulk/interface cooperative engineering in stabilizing the solid-liquid interface and internal phase transitions of Ni-rich cathodes under harsh conditions.

The massive discharge of raffinate acid, a phosphate-rich but impurity-laden by-product of wet-process phosphoric acid (WPA) purification, poses a severe environmental bottleneck for the phosphorus chemical industry. Conventional remediation focuses on costly deep purification, often rendering recovery economically unviable due to the high concentrations of metallic impurities (e.g., Al-3(+), Mg-2(+)). In this work, we propose a closed-loop chemical engineering strategy to directly valorize this hazardous waste into high-value Al-doped LiFePO4/C cathode materials, bypassing the tedious impurity removal process. Unlike traditional protocols, our approach strategically leverages the inherent Al3 + impurity as a functional in situ dopant. Through a facile precipitation-carbothermal reduction route, phosphorus and aluminum species were simultaneously recovered, with Al-3 (+) was successfully engineered into the Fe sites of the LiFePO4 lattice. This "waste-to-resource" mechanism not only stabilizes the crystal structure via strong Al-O bonds but also significantly enhances Li+ diffusion kinetics (D-Li(+) increased by similar to 10 times). The resulting cathode delivered superior electrochemical performance (145 mAhg(-1) at 1 C; 93 % retention after 1000 cycles at 5 C), outperforming the benchmarks derived from high purity reagents. This study demonstrates a sustainable pathway that transforms the environmental liability of WPA waste into a competitive advantage for energy material manufacturing, in alignment with circular economy.

LNMO faces challenges such as rapid capacity decay and unstable cathode/electrolyte interface at high operating voltage. In this study, we constructed a stable cathode/electrolyte interface under high voltage by synthesizing the beta-cyclodextrin-l-lysine-poly (acrylic acid) cross-linked binder (PLC) to increase the cycling life of LNMO at 5.0 V. The PLC binder exhibited an excellent binding mechanism, fast Li-ion transport, and enhanced cathode/electrolyte interfaces stability, which resulted in the capacity retention rate of LNMO/Li half-cells after 1000 cycles at a rate of 1 C. The capacity retention rate of 87.5% after 1000 cycles is significantly higher than the 43.6% of the battery using polyvinylidene fluoride (PVDF) as a binder. This work provides an idea for the research of high-capacity lithium-ion batteries under high voltage.

Nickel-rich layered oxides are the most promising cathode materials for high-energy lithium-ion batteries. However, severe interfacial side reactions negatively affect their stability and electrochemical performance. Adding lithium difluorophosphate (LiDFP) to the electrolyte can prevent surface remodeling and improve interfacial composition, thereby stabilizing the interface. This study compares adding LiDFP to the electrode slurry of the LiNi0.83Co0.11Mn0.06O2 cathode material and electrolyte. When added to the electrode slurry, LiDFP consumes residual lithium on the material surfaces and effectively inhibits the decomposition of electrolyte solvents and lithium salts. Consequently, LiDFP stabilizes the cathode-electrolyte interface and significantly enhances the cycling stability of the materials. The electrode's capacity retention with LiDFP added to the slurry was 87.0 % after 300 1C cycles at 4.3 V, compared to 68.5 % with LiDFP added to the electrolyte. Similarly, the electrode's capacity retention after 200 cycles at 1C and 4.5 V was better than that of the electrode with LiDFP added to the electrolyte. This study suggests new strategies for the practical application of functional additives.

The production of hard carbon for sodium-ion batteries requires a high-temperature calcination process, which leads to substantial energy consumption, stringent equipment requirements, and environmental risks. For mountains of optical fiber waste, this paper proposes a strategy involving preheating and low-temperature calcination to prepare hard carbon with suitable interlayer spacing and mesoporous structures. Subsequently, ball milling and acid leaching are applied to tailor surface defects and pore structure, as well as remove the metal compound coating from the silica core surface. The hard carbon product delivers a discharge specific capacity of 311.92 mAh/g (at 300 mA/g), excellent cycling stability (94.15% capacity retention after 500 cycles at 300 mA/g), and outstanding rate performance (157.83 mAh/g capacity at 2000 mA/g). This synthesis strategy offers a low energy consumption and environmentally friendly approach for preparing sodium-ion hard carbon anode materials.

The expansion of silicon volume significantly impacts the degradation of silicon anodes. The current binder-formed interface fails to effectively suppress this expansion due to the absence of rigid inorganic components. Therefore, we develop an aqueous binder-mediated interfacial engineering strategy to construct an organic/inorganic artificial interfacial layer in situ during the electrode preparation process. This artificial interfacial layer, consisting of an organic alginate-lithium citric acid-tannin derivative (LiACT) binder and inorganic Li2SiO3, is generated by a combination of chemical reactions and hydrogen bonding between tannic acid, citric acid, sodium alginate, silicon, and lithium hydroxide. The three-dimensional structure provides the LiACT binder with a strong binding force. The elasticity of LiACT, the high Young's modulus of Li2SiO3, and their fast ionic conductivity enable this artificial interfacial layer to exhibit robust rigidity-flexibility and excellent ionic- electronic transport properties. Therefore, the Si electrode coated with this artificial interfacial layer (Si@LiACT) exhibits high coulombic efficiency (99.2 % in the 5th cycle), excellent cycling stability (89.2 % capacity retention after 200 cycles), and superior rate performance (1044 mAh g(-1) at 4C). These enhancements are attributed to the unique organic/inorganic artificial interfacial layer, which effectively inhibits silicon volume expansion, alleviates interfacial side reactions, and promotes interfacial charge transfer.

Supercapacitors have shown substantial promise in electrochemical energy storage devices, where porous carbon materials demonstrate exceptional potential applications in their electrodes owing to their high specific surface area, excellent electrical conductivity, and rationally tunable pore architectures. Sodium lignosulfonate and graphene oxide-based porous carbon materials (LC/rGO) were prepared and characterized. The electrochemical performance of the samples was investigated with three-electrode configurations. LC/rGO demonstrated mesoporous architecture and excellent electrochemical performance. The kinetic analysis on the electrochemical properties of the materials revealed an electric doublelayer capacitance (EDLC)-dominated energy storage mechanism. XRD and Raman analysis on the structures of the as-prepared carbon materials suggested a relatively high degree of defects and disorder. Investigations on the morphology, the pore size distributions and the surface chemistry of the samples demonstrated that the materials had a high specific surface area, mesporous structures and multi-atomic doping of nitrogen and oxygen functional groups. All these features could be taken into account for the high electrochemical performance of carbon. LC/rGO as an electrode material demonstrated a high specific capacitance of 296 F g-1 at 0.1 A g-1 and outstanding cycling stability with 97% of the initial capacitance after 10,000 cycles at 5 A g-1 in a 6 M KOH electrolyte. The assembled symmetric supercapacitor using the assynthesized materials exhibited energy density of 10.6 Wh kg-1 at 300 W kg-1 and cycling stability of 95% capacitance after 10,000 charge-discharge cycles, promising for supercapacitor applications.

Ultrahigh-nickel layered oxides (LiNi0.9Co0.05Mn0.05O2) suffer from severe irreversible phase transitions, lattice oxygen escape, and side reactions at elevated temperatures and voltages, leading to performance degradation. To enhance the structural and interfacial stability of LiNi0.9Co0.05Mn0.05O2 under high-voltage and high- temperature conditions, in this work, we developed an in situ ion-exchange strategy to introduce Al3+ doping and an ion/electron hybrid conductive La4(Al1-xNix)LiO8 coating. Comprehensive analysis using X-ray diffraction, X-ray photoelectron spectroscopy, and other techniques, was employed to investigate the effects of Al3+ doping and the La4(Al1-xNix)LiO8 coating on the layer structure, lattice oxygen escape, phases transition, transition metal dissolution, and interfacial side reactions. The synergistic effect of Al3+ doping and the La4(Al1-xNix) LiO8 coating enhanced the structural and interfacial stability, as well as the electrode kinetics, of LiNi0.9- Co0.05Mn0.05O2 at elevated voltage and temperature. The dual-modified LiNi0.9Co0.05Mn0.05O2 exhibited a capacity of 119.6 and 79.8 mAh/g, along with capacity retention rates of 70.4 % and 43.4 % following 300 cycles at 5 C at 4.5 V or 55 degrees C, suggesting enhanced cyclic stability and rate performance under harsh conditions. This work offers a viable strategy for enhancing the structural and interfacial stability of ultrahigh-nickel layered oxides.

Anode-free sodium batteries (AFSBs) guarantee enhanced energy density and safety; however, their practical applications are hindered by uncontrolled dendritic growth and fragile solid electrolyte interphase formation. Hence, a novel interface engineering strategy is adopted in the present work to construct an in situ 3D porous interphase with dual ion/electron conductive channels on aluminum (Al) foil. The interphase consisting of a fast ion-conducting sodium aluminate (NaAlO2)framework, a highly conductive carbon nanotube network, and a flexible carboxymethyl cellulose binder is fabricated through a simple in situ chemical etching method. The unique architecture of the as-prepared interface synergistically regulates the sodiophilic nature and the ion/electron flux distribution, dramatically reducing the sodium nucleation overpotential from 35 mV for bare Al to 15 mV, and enabling ultra-stable sodium plating/stripping in the half cells for over 6000 h at 1 mA cm-2 with a low polarization of 30 mV. When the resultant anode-free full cell is paired with a sodium vanadium phosphate (Na3V2(PO4)3) cathode, it yields impressive high-rate cyclic stability with a retention capacity of 90.7% after 100 cycles at 1 C and a remarkable energy density of 314 Wh kg-1. This work presents a scalable and effective method for stabilizing anode-free configurations and offers valuable insights for next-generation metal-based battery fabrication.

MnPO4∙H2O is an ideal precursor for the preparation of LiMnPO4. However, the instability of Mn3+ in an aqueous solution necessitates the implementation of the existing preparation methods, which are carried out in ethanol and produce toxic gases such as NO and NO2. In this work, a radical-oxidation coupled phosphate stabilization strategy is proposed for synthesizing MnPO4∙H2O in an aqueous solution. The strategy involves the initial oxidation of Mn2+ to Mn3+ by sulfate radicals, which are produced through the thermal activation of Na2S2O8. Subsequently, Mn3+ is stabilized by H3PO4, leading to the formation of MnPO4∙H2O. By implementing this strategy, the mesoporous MnPO4∙H2O precursor can be readily obtained through a reaction at 90 °C for 5 h. Subsequently, the prepared LiMnPO4/C inherits the mesoporous structure of the MnPO4∙H2O precursor, exhibiting excellent electrochemical performance. Specifically, the mesoporous LiMnPO4/C delivers an initial capacity of 115.8 mAh g−1 with a capacity retention of 83.1

K3V3(PO4)4(KVP) is recognized as a promising cathode material for potassium-ion batteries (PIBs) due to its high capacity and robust cycling performance. However, its practical application is hindered by low electrical conductivity. This study reports on the synthesis of K3V3-xLax(PO4)4/C materials with varying levels of lanthanum doping, using sol-gel method. We conducted a systematic investigation into the effects of La3+ doping on the crystal structure, morphological characteristics, and electrochemical performance through physicochemical characterization, theoretical calculations, and electrochemical testing. Theoretical calculations suggest that La3+ doping reduces the band gap energy. Electrochemical tests demonstrate that appropriate levels of La3+ doping enhance the electrochemical performance of K3V3-xLax(PO4)4/C. Specifically, K 3 V 2.98 La 0.02 (PO 4 ) 4 /C shows excellent electrochemical performance. After 100 cycles at 200 mA g- 1 , the discharge specific capacity reaches 59 mAh g- 1 , and after 300 cycles at 400 mA g- 1 , the reversible specific capacity maintains at 48 mAh g- 1 attributed to La3+ doping, which appropriately enlarges the unit cell volume while stabilizing the crystal structure, improving K+ diffusion capability, and boosting the intrinsic electronic conductivity of the material. These findings offer new insights for developing cost-effective and high-performance cathode materials for PIBs. -nearly twice that of the undoped KVP/C. The enhanced electrochemical performance of these materials is

ZSM-5 with mesopores (mesoZSM-5) was prepared using a hydrothermal method. The samples were characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and nitrogen adsorption/desorption at 77 K. The materials were then evaluated for the adsorption of bulk rhodamine B dye molecules from aqueous solution. ZSM-5 with mesopores (mesoZSM-5) was prepared using a hydrothermal method. The samples were characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and nitrogen adsorption/desorption at 77 K. The materials were evaluated for the adsorption of rhodamine B dye molecules from aqueous solution. The prepared mesoZSM-5 was highly crystalline and contained mesopores primarily 15-50 nm in diameter. The material exhibited enhanced adsorption of rhodamine B dye, with a capacity 5.7 times higher than that of conventional ZSM-5. MesoZSM-5 maintained an MFI topology and high mesoporosity. The presence of mesopores addressed the issue of blockage during the diffusion and transport of bulk molecules such as rhodamine B dye. MesoZSM-5 was successfully prepared using a hydrothermal method. The enhanced adsorption of rhodamine B dye demonstrated the critical role of mesopores in facilitating bulk molecular reactions and adsorption activities in zeolites.

K3V3(PO4)4(KVP), a novel cathode material for potassium-ion batteries (KIBs), is recognized for its stable crystal structure and robust cycling performance. Despite these attributes, it is hampered by poor electronic conductivity and limited rate capability. In this research, Fe3+ has been substituted for a portion of V3+ to modulate the electronic structure of K3V3-xFex(PO4)(4)/C, aimed at enhancing its electrochemical performance. Theoretical calculations expectedly show that Fe doping at the V site reduces the band gap energy from 2.674 eV to 1.92 eV, thereby improving electron transfer. Both physical and chemical analyses confirm the successful integration of Fe3+ into the crystal structure and the adjustment of relevant lattice parameters. Additionally, Fe serves as an effective catalyst, enhancing the graphitization of the carbon coating. SEM demonstrates that Fe3+ doping encourages the development of a porous structure, which not only promotes electrolyte penetration but also provides a buffer to the crystal framework during K+ deintercalation. K3V3-xFex(PO4)(4)/C, when doped with Fe3+, shows superior discharge capacity and long-term cycling stability compared to KVP/C. Specifically, K3V2.8Fe0.2(PO4)(4)/C, with an Fe3+ doping level of x=0.2, exhibits minimal electrode polarization and outstanding rate performance. After 380 cycles at 400 mAg(-1), it maintains a discharge capacity of 46 mAhg(-1), significantly surpassing KVP/C. These findings offer valuable insights into the commercial synthesis of scalable, high-performance rechargeable KIBs cathode materials.

Silicon serves as a promising anode material for lithium-ion batteries. However, silicon suffers from low initial coulombic efficiency (ICE) and poor cycling performance due to large volume change, lithium consumption, the formation of a solid-electrolyte interphase (SEI), and low conductivity. To improve the performance of silicon anodes, this work proposed a new strategy for the design of silicon electrode binders based on beta-cyclodextrin, citric acid, and sodium alginate, where a binder with a chemical/ionic/hydrogen-bonded triple-crosslinked network was constructed in situ during electrode preparation. The binder with a triple-crosslinked network provided the silicon electrode with a high binding strength, excellent ion/electron permeation network, and robust interfacial protective layer, providing better tolerate volume changes, and inhibiting the interfacial side reactions and the formation of solid-electrolyte interphase, as well as accelerating Li+ diffusion during the charge/discharge processes. The prepared silicon electrodes had a higher ICE (92.8%), better cycling stability (1429 mAh/g after 400 cycles at 0.5 C), and superior rate performance (1274 mAh/g at 4 C). This work may guide the design of high-performance binders for silicon electrodes.

Due to the higher working voltage of spinel LiNi0.5Mn1.5O4 (LNMO), the electrolyte degrades at high potentials, leading to the generation of numerous alkyl radicals.The transition metals will dissolve under high-voltage reactions, resulting in an unstable LNMO/electrolyte interface, ultimately deteriorating the battery’s cycling performance. In this study, a PAALi-TAc composite binder was obtained through the crosslinking of polyphenolic hydroxides Tannic acid (TAc) with PAALi. The electrode fabricated using this binder achieved a maximum capacity of 132.6 mAh g−1 at a 1C rate. After 100 cycles, the capacity remained at 130.3 mAh g−1, with a retention rate of 98.2%. Even after 400 cycles, the capacity was maintained at 113.2 mAh g−1, with a retention rate of 85.3%. During the 400 cycles of high-current fast charge and discharge at 5 and 10C, the capacity retention rates were 89.3% and 88.0%, respectively. The PAALi-TAc binder played a crucial role in establishing a compatible electrolyte interface by terminating the free radical chain reactions and chelating the excess dissolved metals in high-voltage LNMO//Li batteries, and this led to improved cycling and rate performance.

LiNi0.5Mn1.5O4 (LNMO) is considered one of the most promising cathode materials for high-energy-density lithium-ion batteries (LIBs). However, free-radical-induced carbonate electrolyte decomposition is a key factor hindering the improvement of battery stability. Inspired by the antioxidative properties of ascorbic acid (AA) in scavenging free radicals, the addition of AA during the electrode fabrication process can effectively terminate free radical chain reactions within the cycling of LNMO. This action prevents severe electrolyte decomposition, thus stabilizing the cathode-electrolyte interface (CEI) and ultimately enhancing battery stability. The results demonstrate that LNMO||Li half-cell with the addition of AA show significantly improved cycling performance after 1000 cycles at 1 C, with a high capacity retention rate of 87.4%, surpassing the 43.6% retention rate achieved by batteries using PVDF alone as a binder. This work introduces an efficient and straightforward strategy for designing functional additives to stabilize phase interfaces, offering an economically efficient choice to enhance the electrochemical performance of the LNMO.

Given cobalt's scarcity and high toxicity, there is a considerable interest in nickel-rich materials with reduced or no cobalt content. However, the majority of such materials are polycrystalline particles, which are susceptible to mechanical breakage and structural deterioration during cycling, resulting in rapid capacity decay. Here, we synthesized dispersed and uniform precursors using a poly(vinylpyrrolidone) (PVP)-assisted hydrothermal approach, followed by calcination to produce nickel-rich, cobalt-free single-crystal LiNi0.9Mn0.05Al0.05O2 (NMA) cathode materials. The single-crystal morphology effectively reduced intergranular cracking in the cathode material, preserving phase transition reversibility and cycle stability. At a current density of 0.5C, S-NMA exhibited a maximum discharge-specific capacity of 179.2 mAh g(-1) with a capacity retention of 93.45% after 100 cycles. Additionally, at 55 degrees C and a current density of 1C, it reached 213.6 mAh g(-1) with a capacity retention of 93.3% after 50 cycles. The single-crystal morphology of the cathode material exhibited an outstanding electrochemical performance. This study offers a novel approach to synthesizing nickel-rich single-crystal precursors for cathodes, which holds considerable promise for the advancement of high-performance cathode materials.

Molten salt synthesis is a universal approach to synthesizing single-crystal cathodes. However, complicated processes, such as washing to remove the molten salt and repeated heat treatments, have hindered its practical application in the synthesis of high-Ni NCMs. In this work, using LiNi0.8Mn0.1Co0.1O2 as a model material, a one-step strategy was developed to prepare Li2MoO4-coated and Mo6+-doped single-crystals, where the formation of single crystals, coating, and doping are achieved simultaneously by adding 2% Li2MoO4 as a sacrificial molten salt. The proposed one-step strategy does not require washing to remove molten salt and repeated heat treatment. Furthermore, Li2MoO4 coating and Mo6+ doping can further enhance the structural/interfacial stability and the electrode kinetics of single-crystal LiNi0.8Mn0.1Co0.1O2. Therefore, the cyclic stability (83% after 200 cycles at 1C) and rate performance (169 mAh·g−1 at 10C) of single-crystal LiNi0.8Co0.1Mn0.1O2 is superior to that of polycrystal LiNi0.8Co0.1Mn0.1O2 prepared without the addition of Li2MoO4 (67% and 134 mAh·g−1). This one-step strategy using sacrificial molten salts reveals an attractive pathway for developing single-crystal electrode materials with stable structure/interface and good electrode kinetics.

Manganese oxalate, a cheap anode material for lithium-ion batteries, suffers from a low actual capacity due to its low conductivity. To improve its electrochemical performance, a strategy based on adjusting the reaction temperature was proposed to controllably synthesize manganese oxalates with various morphologies. When the reaction temperature is lower than the boiling point of ethylene glycol, the growth process of manganese oxalate is dominated by the dissolution. The manganese oxalate crystal maintains its initial cubic shape, but its size decreases. When the reaction temperature is higher than the boiling point of ethylene glycol, the initial cubes gradually change into rods through dissolution–recrystallization-oriented growth processes under the high-temperature/pressure environment. The specific surface area and the pore volume of manganese oxalate increase first and then decrease with the increase in reaction temperature. MnC2O4 prepared at 220 °C is a mesoporous rod-shaped particle with the highest specific surface area and pore volume. This sample delivers a capacity of 972 and 949 mAh/g after 500 cycles at 2 and 5 A/g, respectively, exhibiting high specific capacity and good cyclic stability. These results show that the reaction temperature can control the morphology of manganese oxalate by adjusting the crystal growth process, thereby changing its electrochemical properties. Therefore, the results provided further confirm the effectiveness of the proposed strategy.