Despite the high theoretical capacity of Si anodes, their huge volume change and poor electrical connectivity must be overcome by decreasing the feature sizes of the Si particles to the nanoscale and compositing them with highly conductive carbon materials. To ensure the mechanical integrity of the electrodes with uniform dispersion and good electrical contact of the nano-silicon, the industry has to use a relatively low amount of Si (<15% by mass) in commercial anodes. Such a low Si content severely weakens the capacity advantage of silicon at the electrode level. Here, we designed a cellulose-based topological microscroll by the self-rolling of cellulose nanosheets to form a binder-free, flexible, and free-standing electrode comprising an unprecedented 92% silicon content. In the microscroll, carbon-coated silicon nanoparticles are anchored on conductive carbon nanotubes and subsequently confined in cellulose carbon rolls with enough internal voids to accommodate the volume expansion of silicon; thus, a uniform dispersion of silicon with high reactivity was achieved. This structure shows an ultrahigh electrode-specific capacity of 2700 mA h g⁻¹, excellent cycling stability under a high silicon content of 85% (>2000 mA h g⁻¹ after 300 cycles) and a commercial-level areal capacity (5.58 mA h cm⁻²). This strategy offers a new way to design electrodes with a high active material content for high performance batteries.

Wood is gaining increasing attention in applications related to solar steam generation because of its porous structure with microchannels, low heat conduction properties, highly hydrophilic properties and renewability. Wood surface modification is required to improve steam generation performance because of its low optical absorptivity. Unfortunately, the high energy consumption fabrication process and high cost of current photothermal conversion coatings on wood impede its large-scale application. This study develops a facile pyrrole polymerization method to acquire polypyrrole decorated wood (PPy–wood) for solar evaporation enhancement. The black PPy decoration considerably improves the wood light absorption, resulting in a high absorbance (>90%) of PPy–wood within a broad wavelength range, from the ultraviolet region to the near infrared region (300–2500 nm). The combination of advantages related to wood (microchanneled porous structure, high hydrophilicity and thermal insulation) and PPy (broadband and high solar absorption capacity) for easy and fast steam generation makes PPy–wood an ideal solar steam generator, which shows rapid evaporation abilities (1.014 kg m⁻² h⁻¹) and high evaporation efficiency (72.5%) under simulated one sun irradiation. Moreover, the obtained clean water using PPy–wood as the steam generator shows low ion concentrations and high transmittance, demonstrating that PPy–wood possesses excellent potential for seawater desalination and sewage treatment. Thus, such PPy–wood is a potential candidate for water desalination and purification to address water scarcity issues through the effective utilization of clean energy.