To address these challenges, recent efforts have been dedicated to exploring variants of air pumps. These architectures can provide enhanced supplied air pressure and airflow by (i) connecting air pumps in series or parallel \cite{Wehner.2014}, (ii) introducing a double-piston \cite{Kim.2018} or a double-acting pneumatic cylinder \cite{Sridar.2020} to compress more air in a compression cycle, or (iii) using a phase-change medium (dry ice, liquid CO2, DME, etc.) as a pneumatic source \cite{Okui.2018,Wu.2007}. These pump variants indeed improve the actuation speed of m-SPAs, but they also introduce additional challenges related to complicated mechanical design and greater energy consumption.
Meanwhile, some low-power pumps have been developed as a promising alternative to reduce the energy consumption of m-SPAs. For example, based on charge-injection electrohydrodynamics \cite{Cacucciolo.2019} or dielectric fluid-amplified electrostatic zipping structure \cite{Diteesawat.2021}, stretchable electro-pneumatic pumps are reported to operate with a low pump power of fewer than 1 W. However, they suffer from supplying low pressures of less than 10 kPa \cite{Cacucciolo.2019,Diteesawat.2021} or small airflow (161 mL/min) \cite{Diteesawat.2021}. Alternatively, some chemical pumps that utilize fuel combustion or decomposition (CH4, H2O2, etc.) have been designed to provide high pressure (≥ 50 kPa). However, the refueling process and low airflows (≤ 50 mL/min) make them unfeasible to build a compacted low-power system for practical applications \cite{Tolley.2014,Stergiopulos.2014}. Therefore, achieving high-speed and low-energy actuation of m-SPAs remains an open challenge (Table S1 and Figure S1a\cite{Marchese.2014,Drotman.2021,Shepherd.2011,Aubin.2022,Wehner.2014,Mosadegh.2014,Joshi.2021b,Lee.2021,Gong.2016,Yang.2018,Pascali.2022}.