Xiaochuan Ren

Hierarchical Ni–Co sulfides on Ni foam are constructed by successive cation and anion exchange reactions, and the electrode shows excellent energy storage performance as a battery electrode for hybrid supercapacitors.

A ∼24 µm integrated dual-confinement interface enables cathode–anode synergy in separator-free Zn–I ₂ batteries. CNF/Ni-MOF enhances interfacial polyiodide adsorption and conversion, while suppressing water activity, Zn ²⁺ desolvation, and dendrites.

The separator controls ion release, thus inhibiting Zn anode dendrite formation and hydrogen evolution via in situ interface and electrolyte regulation.

Attention to electrochemical energy storage (EES) devices continues to grow as the demand increases for energy storage systems in the storage and transmission of renewable energy. The expanded market requirement for mobile electronics devices and flexible electronic devices also calls for efficient energy suppliers. EES devices applying pseudocapacitive materials and generated pseudocapacitive storage are gaining increasing focus because they are capable of overcoming the capacity limitations of electrical double-layer capacitors (EDLCs) and offsetting the rate performance of batteries. The pseudocapacitive storage mechanism generally occurs on the surface or near the surface of the electrode materials, which could avoid the slow ion diffusion process. Developing materials with beneficial nanostructures and optimized phases supporting pseudocapacitive storage would efficiently improve the energy density and charging rate for EES devices, such as batteries and flexible supercapacitors. This review offers a detailed assessment of pseudocapacitance, including classification, working mechanisms, analysis methods, promotion routes and advanced applications. The future challenges facing the effective utilization of pseudocapacitive mechanisms in upcoming energy storage devices are also discussed.

The challenge with aqueous zinc‐ion batteries (ZIBs) lies in finding suitable cathode materials that can provide high capacity and fast kinetics. Herein, two‐dimensional topological Bi₂Se₃ with acceptable Bi‐vacancies for ZIBs cathode (Cu‐Bi_2−xSe₃) is constructed through one‐step hydrothermal process accompanied by Cu heteroatom introduction. The cation‐deficient Cu‐Bi_2−xSe₃ nanosheets (≈4 nm) bring improved conductivity from large surface topological metal states contribution and enhanced bulk conductivity. Besides, the increased adsorption energy and reduced Zn²⁺ migration barrier demonstrated by density‐functional theory (DFT) calculations illustrate the decreased Coulombic ion‐lattice repulsion of Cu‐Bi_2−xSe₃. Therefore, Cu‐Bi_2−xSe₃ exhibits both enhanced ion and electron transport capability, leading to more carrier reversible insertion proved by in situ synchrotron X‐ray diffraction (SXRD). These features endow Cu‐Bi_2−xSe₃ with sufficient specific capacity (320 mA h g⁻¹ at 0.1 A g⁻¹), high‐rate performance (97 mA h g⁻¹ at 10 A g⁻¹), and reliable cycling stability (70 mA h g⁻¹ at 10 A g⁻¹ after 4000 cycles). Furthermore, quasi‐solid‐state fiber‐shaped ZIBs employing the Cu‐Bi_2−xSe₃ cathode demonstrate respectable performance and superior flexibility even under high mass loading. This work implements a conceptually innovative strategy represented by cation defect design in topological insulator cathode for achieving high‐performance battery electrochemistry.

In order to enhance the ionic conductivity of solid polymer electrolytes (SPEs) and their structural rigidity against lithium dendrite during lithium-ion battery (LIB) cycling, we propose porous garnet Li_6.4La₃Zr₂Al_0.2O₁₂ (LLZO), as the filler to SPEs. The porous LLZO with interlinked grains was synthesized via a resol-assisted cationic coordinative co-assembly approach. The porous structure of LLZO with high specific surface area facilitates the interaction between polymer and filler and provides sufficient entrance for Li⁺ migration into the LLZO phase. Furthermore, the interconnection of LLZO grains forms continuous inorganic pathways for fast Li⁺ migration, which avoid the multiple diffusion for Li⁺ in interface. As a result, the SPEs with porous LLZO (SPE-PL) show a high ionic conductive of 0.73 mS·cm⁻¹ at 30 °C and lithium-ion transference number of 0.40. The porous LLZO with uniformly dispersed pores also acts as an ion distributor to regulate ionic flux. The lithium-symmetrical batteries assembled with SPE-PL show a highly stable Li plating/stripping cycling for nearly 3000 h at 0.1 mA·cm⁻². The corresponding Li/LiFePO₄ batteries also exhibit excellent cyclic performance with capacity retention of 75% after nearly 500 cycles. This work brings new insights into the design of conductive fillers and the optimization of SPEs.