application, and the key challenge lies in the search for suitable electrode materials. Among the available electrode materials for supercapacitors, 2D transition-metal dichalcogenides are superior owing to their higher energy density compared to electric double-layer capacitor-type materials and higher power density compared to battery-type materials. [4] As an alternative, 2H MoS 2 with its good intercalation pseudocapacitive behavior has been extensively used, because its charging/ discharging process occurs not only at the electrode/electrolyte interface but also within the bulk of the material. [5,6] However, its limited interlayer spacing, inferior electrical conductivity, and large volume change upon cycling inevitably cause inferior pseudocapacitance and rapid electrochemical degradation, thus hindering its application in electrochemical energy storage.Recently, hybrid materials formed by assembling electroactive inorganic 2D materials with conducting organic polymers such as polyaniline (PANI), polypyrrole, and poly(3,4-ethylenedioxythiophene) have demonstrated great potential for electrochemical charge storage. [7][8][9] For example, the hybrid of 2H MoS 2 and PANI yielded better specific capacitance and cycling stability than 2H MoS 2 for supercapacitors through the synergistic effect of storing electrolyte ions of different compositions. [10,11] In particular, the electrical potential difference of different Artificial assembly of organic-inorganic heterostructures for electrochemical energy storage at the molecular level is promising, but remains a great challenge. Here, a covalently interlayer-confined organic (polyaniline [PANI])inorganic (MoS 2 ) hybrid with a dual charge-storage mechanism is developed for boosting the reaction kinetics of supercapacitors. Systematic characterizations reveal that PANI induces a partial phase transition from the 2H to 1T phases of MoS 2 , expands the interlayer spacing of MoS 2 , and increases the hydrophilicity. More in-depth insights from the synchrotron radiation-based X-ray technique illustrate that the covalent grafting of PANI to MoS 2 induces the formation of MoN bonds and unsaturated Mo sites, leading to increased active sites. Theoretical analysis reveals that the covalent assembly facilitates cross-layer electron transfer and decreases the diffusion barrier of K + ions, which favors reaction kinetics. The resultant hybrid material exhibits high specific capacitance and good rate capability. This design provides an effective strategy to develop organic-inorganic heterostructures for superior K-ion storage. The K-ion storage mechanism concerning the reversible insertion/extraction upon charge/discharge is revealed through ex situ X-ray photoelectron spectroscopy.

Given the prominent success of the Ga gradient in CuIn 1−x Ga x Se 2 (CIGSe) solar cells, Ge gradient implementation is a promising way to boost Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells. However, Ge-graded CZTSSe solar cells only possess a low efficiency of 9.2%, far from that of Geincorporated CZTSSe without a gradient (12.3%). Herein, we demonstrated a shallow Ge gradient CZTSe solar cell with an improved efficiency over 10%. The Ge gradient was achieved through a GeSe 2 −Se coselenization process, where GeSe 2 acts as a low-temperature fluxing agent to assist crystallization and induce Ge transport toward the back interface. The relieved band tails and improved junction quality, leading to a better carrier separation, were found to take a primary responsibility for device improvement. These results highlight a remarkable breakthrough for Ge-graded CZTSe solar cells and offer a promising way to develop Ge-involved solar cells.

Aqueous Potassium Ion Supercapacitors A covalently interlayer‐confined polyaniline–MoS2 hybrid with a dual charge storage mechanism is developed for supercapacitors. In the hybrid, confined polyaniline induces a favorable phase transition, facilitates cross‐layer electron transfer, and decreases K+ diffusion barrier, thus enabling high electrochemical performance. More details can be found in article number 2204275 by Shude Liu, Seong Chan Jun, and co‐workers.

Sn-free Cu2ZnGeSe4 (CZGSe) is emerging as a promising non-toxic and earth-abundant photovoltaic absorber material due to its attractive electrical and optical properties as well as its high theoretical conversion efficiency....