The large-scale fabrication of high-performance on-chip micro-supercapacitors (MSCs) is the footstone for the development of next-generation miniaturized electronic devices. In practical applications, however, MSCs may suffer from a low areal energy density as well as a complicated fabrication strategy that is incompatible with semiconductor processing technology. Herein, we propose a scalable fabrication strategy for the realization of a silicon-based three-dimensional (3D) all-solid-state MSC via the combination of semiconductor-based electrode processing, chemical vapor deposition, and hydrothermal growth. The individual Si/C/MnO 2 electrode shows a maximum specific capacitance of 223.74 mF cm −2 , while the symmetric electrodes present a maximum areal energy density of 5.01 μWh cm −2 at the scan rate of 1 mV s −1 . The full 3D Si/C/MnO 2 MSC delivers a high energy density of 2.62 μWh cm −2 , at a power density of 117.82 μW cm −2 , as well as a long cycle life with capacitance retention >92% after 4000 cycles. Our proposed method enables the fabrication of 3D MSCs based on a thick silicon interdigitated electrode array, holding a great promise for the development of 3D on-chip microscale energy storage devices.

Transition metal oxides hold great promise for lithium‐ion batteries (LIBs) and electrocatalytic water splitting because of their high abundance and high energy density. However, designing and fabrication of efficient, stable, high power density electrode materials are challenging. Herein, we report rambutan‐like hollow carbon spheres formed by carbon nanosheet decorated with nickel oxide (NiO) rich in metal vacancies (denoted as h‐NiO/C) as a bifunctional electrode material for LIBs and electrocatalytic oxygen evolution reaction (OER). When being used as the anode of LIBs, the h‐NiO/C electrode shows a large initial capacity of 885 mA h g−1, a robust stability with a high capacity of 817 mA h g−1 after 400 cycles, and great rate capability with a high reversible capacity of 523 mA h g−1 at 10 A g−1 after 600 cycles. Moreover, working as an OER electrocatalyst, the h‐NiO/C electrode shows a small overpotential of 260 mV at 10 mA cm−2, a Tafel slope of 37.6 mV dec−1 along with good stability. Our work offers a cost‐effective method for the fabrication of efficient electrode for LIBs and OER.

Lithium is deemed as the anticipated anode for the next-generation energy storage system. Nevertheless, its commercial application is greatly hindered by the uneven deposition and volume expansion in the process of lithium plating and stripping. Here, a three-dimensional lithiophilic current collector with in situ grown CuO nanowire arrays on Cu foam has been demonstrated to effectively ameliorate the above problems. Beneficial from the large specific surface area and lithiophilicity properties, CuO nanowire arrays prominently diminish the local current density and nucleation overpotential, resulting in uniform lithium deposition. Moreover, the optimized anode exhibits a prolonged lifespan for more than 280 cycles at 0.5 mA cm–2 and a high coulombic efficiency of 95.5% for over 150 cycles at 3 mA cm–2 in an assembled half cell, which is maintained steadily for 540 h in a symmetric cell with good capacity retention capabilities in a full cell. This facile approach provides a feasible strategy to realize stable lithium deposition and a high-performance lithium metal anode.

Potassium-ion batteries (PIBs) are of academic and economic significance, but still limited by the lack of highly active electrode materials for de-/intercalation of large-radius K ions. Herein, an interconnected nitrogen/sulfur co-doped carbon nanosheep bundle (N/S-CSB) was proposed as the potassium ions storage material. The rich co-doping of nitrogen/sulfur of N/S-CNB with three-dimensional hierarchical bundled array structure yields distensible interlayer spaces to buffer the volume expansion during K + insertion/extraction, offers more electrochemical active sites to obtain a high specific capacity, and provides efficient channels for fast ion/electron transports. Therefore, the N/S-CSB anode achieved high reversible specific capacity of 365 mAh/g obtained at 50 mA/g after 200 cycles with a coulombic efficiency (CE) close to 100%, high rate performance and long cycle stability. Moreover, the in-situ Raman spectra indicated outstanding reaction kinetics of as-prepared N/S-CSB anode.

Self-supported electrodes represent a novel architecture for better performing lithium ion batteries. However, lower areal capacity restricts their commercial application. Here, we explore a facial strategy to increase the areal capacity without sacrificing the lithium storage performance. A hierarchical CuO-Ge hybrid film electrode will not only provide high areal capacity but also outstanding lithium storage performance for lithium ion battery anode. Benefiting from the favorable structural advance as well as the synergic effect of the Ge film and CuO NWs array, the hybrid electrode exhibits a high areal capacity up to 3.81 mA h cm −2 , good cycling stability (a capacity retention of 90.5% after 150 cycles), and superior rate performance (77.4% capacity remains even when the current density increased to 10 times higher).