Silicon-Carbon (Si-C)

Direct Answer

Silicon-Carbon (Si-C) battery chemistry incorporates a porous silicon-carbon composite matrix into the anode, enabling theoretical lithium capacity up to 4,200 mAh/g (vs 372 mAh/g for pure graphite). Operating at 3.7V–3.8V nominal, commercial Si-C cells achieve gravimetric energy densities of 300–350+ Wh/kg and volumetric densities exceeding 850 Wh/L in ultra-slim smartphone and EV pouch formats.

Source: IEEE / Electrochemical Society Standards · Last reviewed Aug 28, 2026

Specs

Nominal Cell Voltage	3.70 – 3.80 V
Gravimetric Energy Density	300 – 360 Wh/kg
Volumetric Energy Density	800 – 900 Wh/L
Cycle Life (to 80% Capacity)	800 – 1,200 Cycles
Thermal Runaway Threshold	~160 – 210 °C
Operating Temperature Range	-20 to +60 °C
Self-Discharge Rate	1 – 2% / Month
Primary Anode Material	Porous Silicon-Carbon (Si-C) Composite (10–30% Si)
Primary Cathode Material	High-Nickel NMC (Nickel Manganese Cobalt) / LCO

Overcoming Silicon Volume Expansion

While pure silicon can store nearly ten times more lithium ions by weight than graphite, it historically suffered from severe volume expansion (up to 300%) during lithiation. This mechanical breathing pulverized the electrode and degraded the solid electrolyte interphase (SEI) layer after just dozens of cycles. Modern Silicon-Carbon (Si-C) technology solves this by encasing nanoscale silicon particles within a flexible, conductive porous carbon cage or carbon nanotube framework, buffering mechanical stress while maintaining excellent electrical conductivity.

Commercial Adoption in Flagships & EVs

Commercialized rapidly between 2023 and 2025 across premium smartphones (such as Honor's Qinghai Lake battery, OnePlus Glacier battery, and Xiaomi flagships), Si-C chemistry allows devices to pack 5,500–6,500 mAh into bodies previously limited to 4,500 mAh. Automotive manufacturers are adopting Si-C anodes to push EV driving ranges past 800 km without increasing pack weight.