Efficient storage mechanisms for building better supercapacitors. Super capacitors are electrochemical energy storage devices that operate on the simple mechanism of ion adsorption from an electrolyte on a high-surface-area electrode. Over the past decade, their performance has greatly improved due to advances in electrode materials and electrolytes, enabling more efficient storage mechanisms. Porous carbon materials with subnanometre pores exhibit high capacitance due to ion desolvation, while oxide materials store charge via surface redox reactions, leading to the pseudocapacitive effect. Understanding these mechanisms is crucial for further development of supercapacitors. The paper reviews recent progress in understanding charge storage mechanisms in carbon- and oxide-based supercapacitors, using in situ experiments and advanced simulations. It discusses challenges in building better supercapacitors and highlights the importance of understanding the physical mechanisms underlying charge storage. The paper also discusses the development of new materials and architectures for supercapacitors, as well as the role of electrolytes in charge storage. The paper also discusses the development of hybrid supercapacitors, which combine the high energy density of batteries with the high power density of supercapacitors. These hybrid supercapacitors use materials such as Li4Ti5O12 (LTO), which can retain a lithium capacity in excess of 120 mAh g-1 at a charge/discharge rate of 30C. The paper also discusses the potential of oxide-based pseudocapacitors, which can store charge via redox reactions, and the challenges in developing these materials. The paper concludes that the fundamental understanding of ion adsorption and charge storage in supercapacitors is essential for applications and technologies. It highlights the importance of porous carbon-based supercapacitors in energy storage and other applications, and the potential for further improvements in energy density and power density. The paper also discusses the potential of oxide-based pseudocapacitors and the challenges in developing these materials. The paper emphasizes the importance of experimental and theoretical tools in the development of supercapacitors and their applications.Efficient storage mechanisms for building better supercapacitors. Super capacitors are electrochemical energy storage devices that operate on the simple mechanism of ion adsorption from an electrolyte on a high-surface-area electrode. Over the past decade, their performance has greatly improved due to advances in electrode materials and electrolytes, enabling more efficient storage mechanisms. Porous carbon materials with subnanometre pores exhibit high capacitance due to ion desolvation, while oxide materials store charge via surface redox reactions, leading to the pseudocapacitive effect. Understanding these mechanisms is crucial for further development of supercapacitors. The paper reviews recent progress in understanding charge storage mechanisms in carbon- and oxide-based supercapacitors, using in situ experiments and advanced simulations. It discusses challenges in building better supercapacitors and highlights the importance of understanding the physical mechanisms underlying charge storage. The paper also discusses the development of new materials and architectures for supercapacitors, as well as the role of electrolytes in charge storage. The paper also discusses the development of hybrid supercapacitors, which combine the high energy density of batteries with the high power density of supercapacitors. These hybrid supercapacitors use materials such as Li4Ti5O12 (LTO), which can retain a lithium capacity in excess of 120 mAh g-1 at a charge/discharge rate of 30C. The paper also discusses the potential of oxide-based pseudocapacitors, which can store charge via redox reactions, and the challenges in developing these materials. The paper concludes that the fundamental understanding of ion adsorption and charge storage in supercapacitors is essential for applications and technologies. It highlights the importance of porous carbon-based supercapacitors in energy storage and other applications, and the potential for further improvements in energy density and power density. The paper also discusses the potential of oxide-based pseudocapacitors and the challenges in developing these materials. The paper emphasizes the importance of experimental and theoretical tools in the development of supercapacitors and their applications.