Ever-increasing global energy consumption has driven the development of renewable energy technologies to reduce greenhouse gas emissions and air pollution. Battery energy storage systems (BESS) with high electrochemical performance are critical for enabling renewable yet intermittent sources of energy such as solar and wind. In recent years, numerous new battery technologies have been achieved and showed great potential for grid scale energy storage (GSES) applications. However, their practical applications have been greatly impeded due to the gap between the breakthroughs achieved in research laboratories and the industrial applications. In addition, various complex applications call for different battery performances. Matching of diverse batteries to various applications is required to promote practical energy storage research achievement. This review provides indepth discussion and comprehensive consideration in the battery research field for GSES. The overall requirements of battery technologies for practical applications with key parameters are systematically analyzed by generating standards and measures for GSES. We also discuss recent progress and existing challenges for some representative battery technologies with great promise for GSES, including metal-ion batteries, lead−acid batteries, molten-salt batteries, alkaline batteries, redox-flow batteries, metal−air batteries, and hydrogen-gas batteries. Moreover, we emphasize the importance of bringing emerging battery technologies from academia to industry. Our perspectives on the future development of batteries for GSES applications are provided.

Thin solid‐state electrolytes with nonflammability, high ionic conductivity, low interfacial resistance, and good processability are urgently required for next‐generation safe, high energy density lithium metal batteries. Here, a 3D Li6.75La3Zr1.75Ta0.25O12 (LLZTO) self‐supporting framework interconnected by polytetrafluoroethylene (PTFE) binder is prepared through a simple grinding method without any solvent. Subsequently, a garnet‐based composite electrolyte is achieved through filling the flexible 3D LLZTO framework with a succinonitrile solid electrolyte. Due to the high content of garnet ceramic (80.4 wt%) and high heat‐resistance of the PTFE binder, such a composite electrolyte film with nonflammability and high processability exhibits a wide electrochemical window of 4.8 V versus Li/Li+ and high ionic transference number of 0.53. The continuous Li+ transfer channels between interconnected LLZTO particles and succinonitrile, and the soft electrolyte/electrode interface jointly contribute to a high ambient‐temperature ionic conductivity of 1.2 × 10−4 S cm−1 and excellent long‐term stability of the Li symmetric battery (stable at a current density of 0.1 mA cm−2 for over 500 h). Furthermore, as‐prepared LiFePO4|Li and LiNi0.5Mn0.3Co0.2O2|Li batteries based on the thin composite electrolyte exhibit high discharge specific capacities of 153 and 158 mAh g−1 respectively, and desirable cyclic stabilities at room temperature.

The electrochemical reduction of CO2 to produce carbon-based fuels and chemicals possesses huge potentials to alleviate current environmental problems. However, it is confronted by great challenges in the design of active electrocatalysts with low overpotentials and high product selectivity. Here we report the atomic tuning of a single-Fe-atom catalyst with phosphorus (Fe–N/P–C) on commercial carbon black as a robust electrocatalyst for CO2 reduction. The Fe–N/P–C catalyst exhibits impressive performance in the electrochemical reduction of CO2 to CO, with a high Faradaic efficiency of 98% and a high mass-normalized turnover frequency of 508.8 h–1 at a low overpotential of 0.34 V. On the basis of ex-situ X-ray absorption spectroscopy measurements and DFT calculations, we reveal that the tuning of P in single-Fe-atom catalysts reduces the oxidation state of the Fe center and decreases the free-energy barrier of *CO intermediate formation, consequently maintaining the electrocatalytic activity and stability of single-Fe-atom catalysts.