LiNi_xCo_yMn_zO₂ (LNCM)-layered materials are considered the most promising cathode for high-energy lithium ion batteries, but suffer from poor rate capability and short lifecycle. In addition, the LiNi_1/3Co_1/3Mn_1/3O₂ (NCM 111) is considered one of the most widely used LNCM cathodes because of its high energy density and good safety. Herein, a kind of NCM 111 with semi-closed structure was designed by controlling the amount of urea, which possesses high rate capability and long lifespan, exhibiting 140.9 mAh·g⁻¹ at 0.85 A·g⁻¹ and 114.3 mAh·g⁻¹ at 1.70 A·g⁻¹, respectively. The semi-closed structure is conducive to the infiltration of electrolytes and fast lithium ion-transfer inside the electrode material, thus improving the rate performance of the battery. Our work may provide an effective strategy for designing layered-cathode materials with high rate capability.

Vanadium redox flow batteries (VRFBs) are one of the most attractive devices for grid-scale energy storage due to their advantages of high safety, flexible assembly, and electrolyte-class recycling. However, the conventional graphite felt electrodes usually possess inferior electrocatalytic activity for vanadium ion redox reactions, vastly limiting the rate and lifespans of VRFBs. Herein, we demonstrate a high-rate and ultra-stable vanadium redox flow battery based on quaternary ammonium salt-modified graphite felt electrodes. At a high current density of 200 mA cm⁻², the constructed VRFB exhibited a superior cycling life of up to 1000 cycles. This work affords a straightforward approach for developing efficient, environmentally friendly, and low-cost graphite felt electrodes for ultra-stable and high-rate VRFBs.

Cadmium (Cd) contamination in agricultural soils has caused extensive concern to researchers. Biochar with iron-compound modifications could give rise to the synergistic effect for Cd restriction. However, the related capture mechanism based on physicochemical properties is unclear. In this study, first principles calculations are proposed to explore the adsorption ability and potential mechanism of the ferric hydroxide modified graphene (Fe@G) for capturing CdCl₂. The simulation results show that the adsorption energy to CdCl₂ could enhance to −1.60 eV when Fe(OH)₃ is introduced on graphene. Subsequently, analyses of electronic properties demonstrated a significant electron transfer between Cd s-orbital and O p-orbital, thereby leading to strong adsorption energy. This theoretical study not only identifies a powerful adsorption material for Cd reduction in agricultural soils and reveals the capture mechanism of Fe@G for Cd but also provides a foundation and strategy for Cd reduction in agricultural soils.

Vanadium-bearing wastewater threatens aquatic ecosystems and human health, calling for efficient, low-cost adsorbents. In this study, low-temperature pyrolytic carbon rich in oxygen-containing functional groups is prepared from Camellia oleifera fruit shells (COS) and modified with KMnO₄ to obtain a carbon–MnO₂ composite (BC-KMnO₄). The adsorbents are characterized by XRD, FT-IR, XPS, Raman, N₂ adsorption–desorption, and SEM, and their vanadium adsorption performance is evaluated through batch experiments, isotherm and kinetic modeling, and DFT–MD simulations. KMnO₄ modification introduces δ-MnO₂ nanoparticles together with additional oxygen-containing functional groups. Under certain test conditions (m = 1.2 g, T = 70 °C, C₀ = 300 mg L⁻¹, V = 100 mL, t = 72 h, pH = 5), BC-KMnO₄ exhibits a high adsorption capacity of 24.76 mg g⁻¹, exceeding those of pristine biochar (14.52 mg g⁻¹), COS-KMnO₄ (22.65 mg g⁻¹), and pure MnO₂ (13.25 mg g⁻¹). The regeneration cycle test of the adsorbent demonstrates that the adsorbent possesses favorable short-term laboratory reusability. DFT–MD simulations further reveal that oxygen-containing functional groups and MnO₂ synergistically enhance adsorption, with C-TO/MnO₂ displaying the lowest surface electrostatic potential and the highest adsorption energies toward H₂VO₄⁻ and HV₂O₅⁻. The composite retains its structure after adsorption. This work offers an instructive strategy for the high-value production of biomass-derived carbon adsorbents.